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Impacts of remote sensing on U.S. geography
REMOTE SENSING OF ENVIRONMENT 10 43-80 (1980)
43
Impacts of Remote Sensing on U.S. Geography
JOHN E. ESTES, Department of Geography, Unwersttyof California, Santa Barbara, California 93108
JOHNa JVNSEN, Departnwnt of Geography, Umversttyof Gecrtg~ Athens, Georgia30610
and DAVID S SIMONETT Department of Geography, Universityof Caltfom~ Santa Barbara, California 93108
Tim paper exarmnes some tmpacts of remote sensmg on geography As geographers revolved m tim new technology, we revtew and place in context its development, and with a vmon of zts value to our chsc~pime, we are concerned at Its modest unpact on major research areas in geography Even acknowledging that, m a broader vaew, remote sensmg's LmpaCt on geography has been greater than m other disciphnes does not allevmte our concerns that few semor acadennc geographers have remote sensmg research underway, that few economic geographers have exammed its potential, that even fewer regional geographers wtth interests m less-developed countries have remote sensing research interests, and that although there has been growth m the number of remote sensing courses taught in geography, tim has not been accompamed by pubhcaUon m reviewed geograpluc Journals We ask the questaons. What does remote sensing Pernut the geographer to do better a n d / o r cheaper than he or she could do m the past? What may remote sensing enable future geographers to do wluch would be sagndicant to professaonal and academtc geography? We then find that the exploitalaon of the unproved or umque mforn~tmn avadable to the geographer wa the apphcation of remote sonsmg techmques has barely begun Yet, remote sensing ts a reahty within geography whose tune has come It ts too powerftd a tool to be ignored m terms of both its mformalaon l~tenttal and the logic tmphcit m the reasoning process employed to analyze the data We pre&ct xt could change our Perceplaons. our methods of data analysts, our models, and our paradagrns
Introduction Tlus paper examines some of the impacts of remote s e n s m g - - a relatively new t e c h n o l o g y - - o n geography, a dasclplme which traces its origins back to the beginning of learmng. As geographers deeply revolved in this new technology and with a vision of Its future value to our daselphne, we are concerned at its relatavely modest impact on some major research areas in the chsclphne Even ac©Elsevier North Holland Inc. 1980 52 Vanderbdt Ave. New York, NY 10017
knowledglng that m a broader view of t h i n g s r e m o t e sensmg's impact on geography has been as great or greater than m other &sclphnes does not alleviate our concerns over the following. (1) few semor academics in geography have research underway m remote sensing, (2) few economic geographers, who conshtute a sizable body of geograplucally trained professionals, have examined, or have reahzed the potentaal of remote sensmg, (3) even fewer regional geogra0034-4257/80/0~1043 +38501 75
44
phers (notable among them are those with teaching a n d / o r research interests in the less developed countnes) have remote sensing as a professlonal research interest, and (4) although there has been a growth in the number of remote sensing related courses offered by geography departments, this has not been accompained by an increase m research publlcatlon in rewewed geographic journals In the followmg pages, these concerns are exammed, along with a number of encouraging signs such as the relatave strength of remote sensing among physical geographers and especially among cartographers Indeed, there are a number of simdantles between the growth of cartography within the chsclphne and the growth of remote sensmg From an academic/institutional standpoint cartography has made tremendous stndes since the 1950s whde remote sensing appears to have begun similar expansion m the mld-1960s. To set the stage for the dascusslons which follow, a brief history of remote sensing within geography is put forth The current status of remote sensing within the profession is then exarmned with primary emphasis on academm and to a lesser degree on the government and private sectors. The paper concludes with an extended chscusslon of the abdlty of remotely sensed data to prowde reformation witinn the context of the explanatory forms typically used by geographers (Harvey, 1969). Tins is accomphshed within a framework of the questions. (1) What does remote sensing permit the geographer to do now better and~or cheaper than he or she was able to do m the past? (2) What does remote sensing permit the geographer to do now that he or she was unable to do in the pastg, and
j E ESTES, J B JENSEN AND D S SIMONETr
(3) What may remote sensing enable geographers to do m the future winch could be of slgnLFlcance to professional and academic geography? T h e Past In Perspective
The Instoncal development of aenal photographic mterpretataon (later remote senlsng) within geography has gone through a number of stages as suggested In part by Stone (1974)' 1.
.
.
.
.
From 1858 to about 1930 there was very slow recognition that the first photographs taken from the air had utility for mapping. Near the end of this period, experimental use of air photos began in oval enganeenng, forestry, soft conservation, and mapping apphcataons. These later developments coupled with rapid wartime development of air-photo interpretation as a sophisticated lntelhgence gathenng technique form the basis for a second period (1920-1950). A period of technique refinement developed during the transition from wartime to peacetmae (1950-1962). A brief phase with pnmary emphasis on the a p p l i c a t i o n s of air-photo interpretation to geographic problems (1955-1962). The adjustment of these apphcatlons to the expansion of data gathering and analysis into nonvisible regaons of the electromagnetic spectrum (1962 to present). Finally, a period winch is just beganning, in which lnformataon from a variety of platforms, systems, times, and scales are analyzed and used as malor sources of data for modehng
IMPACTS OF REMOTE SENSING
complex enwronmental phenomena (1972 to present). As can be seen from the tame spans associated with these stages, there is overlap. This to be expected within the dlsclphne since development, acceptance, and apphcatlon are not mdependent
To 1930
Although aerial photography had been avadable for some 40 years, it was near the beglnmng of the Twentieth Century when geographers in the Umted States began to reahze the potential of mr photos as an md to geographic research. Dunng World War I, geographers m mdltary units began to see slgmficant peacehme uses for this early nnhtary coverage The first major geographic pubhcatlon on the subject in the Umted States was the American Geographical Society's Special Pubhcataon No. 4, The Face of the Earth as Seen from the Air, by Wdhs T Lee, pubhshed in 1922. This book introduced American geographers to the concept of vaewlng "farmhar scenes from a new angle," 1 e , the aerial perspective Other pioneering works of the period include Joerg's "The Use of Atrplane Photography m City Geography" (1923) and Johnson and Platt's Peru from the Air (1930). In the 1920's, aerial photography in the Umted States was acqmred for topographic mapping purposes. Interpreters working with these photos stressed the cartographic aspects of the coverage. As this work progressed, realization of the topographic and geographic (particularly agricultural) reformation content of these data led to the long-term program of photographing the
45
entire Umted States at regular intervals begmnmg about 1930. 1920-1950
The plan to photograph the whole nation lnltaally had two primary objectives. First was the goal of conducting mechum-scale topographic mapping of the whole nation. The second objectave was the large-scale mappmg of agricultural areas for government subsidy payments which were based on the field acreage of farms revolved xn crop payment programs. Interestangly, as the Department of Agriculture obtmned additional coverage, few geographers experimented vclth the photographs Roscoe (1960) attributed this early reluctance of the geographic commumty to (1) a lack of training in mterpretataon techmques and the relatwe difficulty of acqmnng copies of photo coverage, (2) the mtdtlple objectives of geographic mvestagatlon and the fact that some geographers avoided the use of aerial photos because they could not Identify all objects imaged m a scene, and, (3) the lack of commercial demand for the geographer's mterpreted product. It is probable, however, that some of this lack of appllcataon reflected changes m the basic objectives of American geography. The formerly strong emphases on physical geography were weakemng in favor of more culturally oriented man-land relations (Stone, 1974). 197.0-1950
During World War II, mr-photo interpretation came into its own as an mtelhgence gathering technique. Geographers, both foreign and domestac, were trained as photo interpreters. Interpretation was
J E ESTES, J n JENSEN AND D S SIMONETr
46
accomplished at two levels, tactical and strategic. Emphasis was placed on the preparation and use of "keys" by which Identfflcahon of items of mthtary mgnLflcance could be made rapidly regardless of an interpreter's prevaous experience This wartime exposure prowded excellent training, quahfylng many geographers for peacetime apphcatmns and instruction American geographers experimented wath aerial photography wath regard to both systematic topics and areal differentiation. Geographers began to take photos to the field trying to determine causes of observable chfferences in texture and tone An early artacle by Russell et al. (1943) is a classic dlustration of the use of aenal photography for overall inventory The analysis of mr photos for small-scale geographic studies also continued (Bach, 1942, Light, 1944). In
addition, an arhcle by Stone (1948) on Alaskan vegetation keys provided an excellent example of the value of smallscale coverage (1 35,000 to 1 50,000) for land classification. However, by the end of the period, the pnncipal geographical articles pubhshed in the United States were stdl largely general and descnphve (Cads, 1947, Long, 1947, Stokes, 1950, Foster, 1951, Kohn, 1951, Kesseh, 1952, MacFadden, 1952). 1950-1960
This penod saw the expansion of aerial photographic interpretation in college geography curricula and a rapid diversification of techniques and instrtunentation By 1950, some 13 geography departments, all east of the Mississippi Raver, offered courses in aerial photographic interpretation (Fig. 1) The main con-
Inshtutuons Offering Geography Courses nn Anrphoto Interpretahon 1950- 51
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IMPACTS OF REMOTE SENSING
47
centratlon of these schools was I n t h e northeastern United States, from Ilhnols and Wisconsin m the west to Massachusetts m the east A small discontinuous concentrahon existed m the south w~th courses taught in Lomslana, Alabama, and Georgaa (Schwendeman, 1951) By 1960, the number of restitutions offenng courses in aerial photographic Interpretation had grown to 25 (Fig 2) The pattern in 1960-1961 indicates defimte geographical shifts with schools on the Pacific Coast as well as in Colorado and Utah offenng new courses and some mshtuhons in the Northeast no longer represented (Schwendeman, 1961). In 1960, of the 25 lnshtutlons teaching aerml-photographlc lnterpretahon, 20 offered graduate degree programs m geography (see Table 1)
Dunng th~s time, geographers were stdl working on the development of interpretation keys for physical and cultural dements of the landscape (Black, 1955; Levels, 1957, Kedar, 1959) Some mvestlgahons of the potentml of automated image analys~s were also ~mtaated (Latham, 1959) In general, it is safe to say that most work of the period was overly optlm~shc in spite of occasional warnings (Stone, 1974) Also, geographical writings on problems employing airphoto interpretation techmques dtmng this time were still pnmardy descnphve and lacked thorough penetrating analysis (Stone, 1954, Stone, 1956, Kline, 1954). 1955-1962
Beginning about 1955, emphasis in geographic works using aerial photography
Inst=tut=ons Offering Geography Courses m A=rphoto lnterpretat=on 1960 - 61
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EAGI73revCEDI77
48
J E ESTES, J B JENSEN AND D S SIMONETF TABLE 1 Inslatutmm with Geography Offenngs m Au'photo Interpretation/Remote Sen~n~ STATE
N ~ m OF Umvr.nsITY
Alabama
Umv of Alabama, Tuscaloosa
Arizona
Arizona State Umv, Tempe N Arizona Umv, Flagstaff Umv of Arizona, Tucson
Cahforma
Cahforma State Umv, Chteo Cahforma State Umv, Dommguez Cahforma State Umv, Fresno Caldorma State Umv, Fullerton Cahforma State Umv, Hayward Cahforma State Umv, Los Angeles Cahforma State Umv, Northndge Cahforma State Umv, San Dxego Cahforma State Umv, San Jose Humbolt State Umv, Arcata Sonoma State College, Rohnert Park Umv of Cahforma, Daws Umv of Cahforma, Los Angeles Umv of Cahforn~ Paversnde Umv of Cahfornla, Santa Barbara
Colorado
1950-1951
1960-1961
1971-1972
1975-1976
O
O
•
•
•
• A •
O
[] •
• [] • 0
•
• •
• •
• •
• • A •
•
0 • • • •
•
A 0 [] • • •
Central Connecticut State College, New Bntam
0
0
Delaware
Umv of Delaware, Newark
•
•
DC
Cathohc Umv of America
•
•
Flonda
~ o n d a A ~ n b e Umv, Boca Baton Flonda State Umv, Tallahass~ Rolhns College, Wmter Park Umv of Flonda, Gameswlle
• •
• •
Conneetaeut
Adams State College, Alamosa S Colorado State College, Pueblo U S Atr Force Academy, Colorado Springs Umv of Colorado, Boulder Umv of Colorado, Denver Umv of Denver, Denver
0 • • • []
•
•
O •
•
•
• A
Georgia
Umv of Georg~ Athens W Georgia College, Carrohton
Hawaii
Umv of Hawan, Honolulu
•
•
Idaho
Umv of Idaho, Moscow
A
A
mmms
Augustana College, Rock l~land Illmms State Umv, Normal N E Ilhnots Umv, Clucago Northern mmms Umv, DeKalb Northwestern Umv, Evanston S Illmms Umv, Carbondale S Illinois Umv, Edwardsvdle Umv of Ilhnots, Urbana W Hhno~ Umv, Macemb
Ind,ana
Anderson College, Anderson Ball State Umv, Munc~e Indmna State Umv, Terre Haute
0
•
• • •
A • • •
• • •
• •
• •
• • •
• •
•
•
•
IMPACTS OF REMOTE SENSING STAT~
NAME OF UmVEBSIT'Z Induma Umv, Bloomm~on Induma Umv, S E , Jefferson Induma Umv, New Mbany
49 1950-1951
1960-1961
1971-1972
1975-1976
•
•
• •
• O
Iowa
Umv of Northern Iowa, Cedar Falls
Kansas
Umv of Kansas, Lawrence Wichita State Umv, Wlcbata
• O
• O
Kentucky
Eastern Kentucky Umv, Pachmond Umv of Kentucky, Lexington Umv of I.~msvdle, Lomsvdle Western Kentucky Umv, Bowling Green
• • O
• • O
•
•
•
• A O O
•
• O •
LonlgLana
Lomsmna State Umv, Baton Rouge Loo~qmna State Umv, Shreveport Nleho~ State Umv, T~bodaux Southern Umv, Baton Rouge
Maryland
Frostburg State College, Frostburg Towson State College, Towson Umv of M a ~ n ~ College Park
Massachusetts
Boston Umv, Boston Clark Umv, Worcester Fitchburg State Cofiege, Fitchburg Frammgham State College, Frammgham
•
•
•
•
• • •
• • O O
•
• • 0 •
O • •
• 0 • •
Mtsstss~ppl State Umv, Mtss~sappl Umv of S Mlsslssapph Hathesburg
•
• •
Montana
Montana State Umv, Bozeman Umv of Montana, Mmsoula
• •
Nebraska
Umv of Nebraska, Lincoln Umv of Nebraska, Omaha
Nevada
Umv of Nevada, Las Vegas
Mlehagan
Mmn~ota
Mms3ssippl
Central Machtgan Umv, Mt Pleasant Mle~gan State Umv, East Lansmg Northern IVhchtgan Umv, Marquette Western Michigan Umv, Kalamazoo
•
Mankato State Umv, Mankato Moorhead State College, Moorhead St Cloud State College, St Cloud Umv of M m n ~ o ~ M m n ~ p o ~
•
• • []
New Hampslure Dartmouth College, Hanover New Jersey
Princeton Umv, Pnnceton Rutgers Umv, New Brunswaek
New Me~aco
New Mexico State Umv, Las Cruces Umv of New Me~aco, Alburquerque
New York
Bnarchff College, Bnarchff Manor Columbm Umv, New York Hunter College, New York State Umv of New York, Albany State Umv of New York, Bmghamton
• •
A
A
0 •
•
•
0 •
• • •
[] • O • •
50
J E ESTES, J R JENSEN AND D S SIMONETT STATE
NAMEoF UmVeSSITY
1950--1951 1960--1961 1971--1972 1975-1976
State Umv of New York, Plattsburgh State Umv College, Buffalo State Umv College, Cortland State Umv College, New Paltz State Umv College, Oneonta Syracuse Umv, Syracuse
0 0
A 0
North Carohna Appalachan State Umv, Boone East Carohna Umv, Greenvdle Umv of N Carolina, Chapel I-Idl Umv of N Carolina, Charlotte North Dakota
Umv of North Dakota, Grand Forks
Oho
Bowling Green State Umv, Bowlmg Green Kent State Umv, Kent Mmrm Umv, Oxford Mu_qkmgumCollege, New Concord Oho Umv, Athens Umv of Akron, Akron Wittenberg Umv, Springfield Wnght State Umv, Dayton
0
0 0 0
0
@
0
Oklahoma
East Central State College, Ada Umv of Oklahoma, Norman
0 B
0
Oregon
Oregon State Unlv, Corvahs Portland State Umv, Portland Umv of Oregon, Eugene
0
O
Pennsylvania
Indmnu Univ.of,Penn,, Ivdtana Lock Haven State C611e~e, Lock Haven PennsylvaniaState Univ., State Q~llege Temple Univ, Phdadelphta Umv of Ptttsbur~ lhttsburg
O
South Carolina Univ. of South Carolina, Columbm South Dakota
South Dakota State Univ, Brooklings
Tennessee
East Tenn State Untv, Johnson City Memphis State Umv., Memphis Umv of Tennessee, Knoxvdle
Texas
North Texas State Umv, Denton SW Texas State Univ, San Marcos Umv of Texas, Austm
Utah
Brigham YoungUmv,, Provo Umv of Utah,'Sa]t Lake City Weber State College, Ogden
[]
0 A
0
0 0
Vermont
Umv of Vermont, Burlington
Vn~ima
Mary Washmgton College, Fredncksburg Umv of Vrrgrma, Charlottesvdle
0
Wm~hmgton
Central Washington State College, Ellesburg East W~hmgton State College, Cheney Umv of Washington, Seattle
O O
IMPACTS OF REMOTE SENSING STATE
N m ~ OF UmanmasirY
51 1950-1951
1900-1961
1971-1972
1975-1976
0
0 A
0 A
o o o
[]
Western Washington State College,
BeUmgham Wtsconsm
Wyommg
Beirut College, Beirut Cardinal Stntch College, Mdwaukee Umv of Wtsconsm Green Bay Umv of W~consm La Crosse Umv of Wtsconsm Madison Umv of Wmconsm Mdwaukee Umv of Wtsconsm Oshkosh Umv of Wmeonsm PLattevdle Umv of Wtsconsm Stevens Pomt Umv of Wh~onsm Whtewater
[]
0
Umv of Wyomm~ Laranue
a Undergraduate Graduate O A
[]
• •
•
Axr-photo mterpretalaon Remote sensmg Atr-photo mterpretatmn and remote sensmg
began to be placed on the analysis and significance of the data rather than on techmque. This is documented by bibhographles compded shortly after the end of this period (Honea and Prentace, 1966; 1968, 1970). Early applications were related to upgrading the lnforrnatlon base and improving the understan&ng of specific urban problems, such as the distributions of neighborhoods with differing levels of economic status, traffic chrectlon and volume, industnal plant location and classification, mapping of land use zones, developmental planning, and the extension of census data using aerial photos (Green, 1956, 1957, Green and Morner, 1959) Important progress was also made m upgrachng information extractaon potentaal of aenal photography m the study of landforms and rural cultural features (Powers and Kohn, 1959). Agricultural apphcataons were significantly advanced through the use of mr photos for the identification of crops in various growth stages as an element of land-use analysis (Burnschweder, 1957, Goodman, 1959,
Karan, 1960). On the physical side, the mterpretataon of natural vegetataon was also examined m detail (Finley, 1960) It is important to note that many uses of aerial photography were buried in the content of the geograpbacal work dunng this tLrne. Only occasionally did footnotes disclose the dependence of research on aerial photography as a primary data source.
1962-Present
A great deal of activity has occurred within geography dunng tlns tame period. In order to facilitate discussion, the actavltaes of geographers during this tame frame are broken down into a number of categories. These include academia, symposia, iournal artacles, texts and reference works, research funchngs, and, professional society, private industry and federal, state, and local government actawtaes Academia In the early 1960s, the expansion of course offenngs m geography accelerated coincident with the mtroductlon of the term "remote sensing" and an
52
j E ESTES, J R JENSEN AND D S SlMONETr
increased interest within the federal government in aerial reconnaissance as a means of obtaining environmental reformation By 1971-72 (based on reformation from S c h w e n d e m a n , Sr. a n d Schwendeman, Jr. 1972, and Eltel, 1972, and response to questionnatres dastrlbu t e d to G e o g r a p h y departments throughout the nation), Estes and Thaman (1974) found that 99 restitutions m 37 states and the District of Columbia offered courses m either remote sensing or aerial photographic interpretation (Fig. 3, Table 1) The pattern expressed by the 1971-72 dlstrlbutaon is one of intrastate expansion and fllhng in between the three nodal areas seen in the 1960-61 chstnbutaon (Fig. 2) Of the 99 mstltutaons m 37 states, some 74 restitutions in 35 states offered graduate programs in geography (Table 1). Thus, in
httle more than a decade, there was an increase of almost 300% m mstltutaons offenng courses and a gain of slightly over 100% m the n u m b e r of states where these courses were offered. Furthermore, there was also a 300% gain in offenngs at schools with undergraduate programs, along with a 120% gain in states with graduate programs (Table 1). In 1975-76, the total n u m b e r of departments offenng courses in remote sensing a n d / o r air-photo interpretation was 165 (Table 1) These 165 departments are m 44 of the 50 states (Fig. 4) (Schwendeman, Sr and Schwendeman, Jr., 1976). The only states where, to the best of our knowledge, departments of geography do not currently offer either remote sensing or photo interpretation are Alaska, Arkansas, Maine, Missouri, Rhode Island, and West Virginia. Thus,
Institutions Offering Geography Courses in Airphoto Interpretation / Remote Sensing 1971-72
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N o c o u r s e s offered and Graduate
refer to d e p a r t m e n t a l
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FIGURE 3
EAG/73 rev CED/77
IMPACTS OF REMOTE SENSING
53
since 1971-72 there has been continued expansion in the number of lnstatutmns offenng remote sensmg/atr-photo interpretation (a 40% increase over the 1971-72 figures) A recent article by Nealey (1977), based on responses to questmnnalres marled to restitutions across the country, hsts a total of 103 courses taught in geography departments in remote sensing and related topics. This total represents 22% of a nationwide total of 470 courses in all &sclphnes ldentffaed in his study Even if we accept the mconsistency between Nealey's and our data to be equal for all dlsclphnes (Nealey's 103 courses to our 165), geography's role in remote sensing Instruction is still sigmficant. Geography teaches more mrphoto interpretation and remote sensing courses than any other disctpline m the COU l't t r y
To provide this work with a flavor of current research being conducted by geographers in umversitaes and colleges across the Umted States today, the authors sent letters requesting mdwlduals to provade mformataon concermng their research. From responses received, ~t appears that along wath the mcrease in numbers of courses taught, as noted above, geographers wathm academia have continued to pursue research into the applicataons of remotely sensed data in a vanety of analytical and methodologacal studies Basically expanding on the trend begun in the mld-1950's, geographers have placed heavy emphasis on the analysis and significance of the data, yet in this period with the rapid expansmn of the avatlablhty of data from a variety of systems (actave and passive microwave, thermal infrared, etc.) and platforms
Institutions Offering Geography Courses m A~rphoto Interpretation/ Alaska
Undergraduateo
[3
Graa~uate •
[~
•
Remote Sensing Atrphoto Interpretation and Remote Sensing No courses offered
note Undergraduate and G~aduate refer to departmental status only
FIGURE 4
CED/rr
] E ESTES, i R JENSEN AND D S SIMONETT
54
(both low- and high-altitude and spacecraft), articles wath emphasis on techmques and methodology have begun to reappear Of the responses received, those which are not included m the following section deahng with a more recent trend m geographic remote sensing (1972-present) include. .
Methodological works by: Hsu (1975) on automated pattern recognition of thermal infrared data. The use of a specmhzed (Mahalanobls) classffaer m automated image processmg (Hsu, 1978), and population estamataon from Landsat data (Hsu, 1973) Eyton and others m interpretation and data processing (Eyton, 1978). A process for enhancing the interpretability of Landsat data (Eyton and Kuether, 1978). Klemas and others on the vanablhty of wetlands reflectance and ~ts effect on automatic classification of images from Landsat (Bartlett and Klemas, 1977) An approach to studying estuanne clrctdataon and shelf waste dispersion using satelhte-mrcraft-drogue data (Klemas et al. 1974). Kraus and others on the comparatave detection of marine surface targets as interpreted from real and synthetic aperture radar data (Kraus, et al., 1977). McDonnel and Lewis (1978) on the detection of ship targets on Landsat imagery. Estes and others on the measurement of sod moisture conchtlons wath an airborne imaging passwe microwave radiometer (Estes et al., 1977). Welch (1977) and Welch and Lo's (1977) works on speclflcataon and analysis of image quality and height measurement from satellite data
Tmney and others on the mapping of archaelogical sites from historical vertical and obhque photographs (Tmney et al., 1977). Thomas, Lewis and others on the assessment of snow pack from Landsat data (Thomas et al., 1978), and by Lewis (1977) on coastal mapping wath radar systems 2. Work on land-use/land-cover analysis by Klemas and others on classification of coastal zone land-use patterns from satelhte data (Klemas et al, 1975). Peterson and others on an inventory of the wetlands of the state of Nebraska using Landsat satellite data (Seevers et al., 1975). Rehder on changes which occur m the landscape as a result of strip mlnmg (Rehder, 1976), and momtorlng landscape change from Landsat data (Rehder, 1973) Mower and others on the development of a computer processed land-cover map of the state of North Dakota (Mower and Helnrlch, 1977); and on the dlscrtmmatlon of land and water resources using multtspectral remote sensing techmques (Mower, 1976). Walsh (1978) on dafferentlatlon and mapping of coniferous tree species. Henderson (1977) on the use of radar imagery m the analysis of Land-use patterns. 3 Works on areas outside the United States by. Comer (1977), on apphcatlons of remote sensing to the development of urban information systems m In&a. Klemas on the apphcatlon of satelhte data to the management of food resources m developing countries (Klemas and Leu, 1977). PanneU and Welch (1976) on recent satelhte coverage of Cbana. (Welch and Pannell, (1975) on investigation
IMPACTS OF REMOTE SENSING
of recent urban land-use change in Northeast China, and (Lo, et al., 1977) on land-use changes and city planmng m Shenyang and Canton, China. In addition to these pubhshed works, researchers under Ray Lougeay are workmg on the use of Landsat data for the mapping of buried glacier ice. Norbert Psuty and researchers at Rutgers Umverslty are working on the analysis and delineation of submerged coastal vegetation. Ramer Erhart at Western Michigan University is working with Raymond Price on the ongan of hnears in a glacial environment in Southwestern Mlchtgan. Gary Hlggs of Mississippi State Umverslty is mvestagatmg the applications of remote sensing to a variety of land-use/ land-cover topics lncluchng beach erosion and cotton mapping. Symposia A factor which has contnbuted to the growth of interest m remote sensing in the United States is the increasing number of remote sensmg symposia, the first and still most prestaglous symposia being the senes conducted by the Envaronmental Research Institute of Michigan (ERIM) at the Umverslty of Michigan and other sites. This symposmm senes resulted initially from recommendations of a subcommittee of the National Academy of Sciences--National Research Council and the Geography Branch of the Office of Naval Research (Institute of Science and Technology, 1963). The subcommittee met in January 1961 to discuss the need for more advanced and efficient data acqmsltaon techmques m the earth sciences. The symposia were imtaated to provide a periodic forum for assessmg developments m the field of remote sensing
55
The First Symposmm was held in February 1962. There were 72 partlclpants including five geographers. At the Seventh Symposmm, held m May 1971, there were 850 partaclpants, lncludmg 46 geographers (Fig 5) At the Tenth Symposmm (1975) there were 16 geographers out of 645 attendees, whde at the Eleventh Symposmm held m April, 1977, there were only 8 U S geographers out of 497 registered attendees. One paper (of 15) was presented by a United States geographer m 1962, 12 (of 173) m 1971, 12 (of 132) m 1973, 9 (of 155) m 1974, 5 (of 146) m 1975, 9 (of 172) m 1977, and 11 (of 226) m 1978. Respectively, these percentages are 7, 7, 9, 6, 3, 5, and 5. Whether the absolute decline in attendance at these symposia and m the relative number of papers presented by geographers in recent years is real and reflect a disinterest among geographers m research in remote sensing, or whether it is an artifact, we do not know. There are now other remote sensing symposia which draw geographers away, and the Michigan Symposia are also held each year at a time near to or coincident w~th the annual meeting of the Assocmtion of American geographers (which in adchtaon now schedules 3 to 5 sessions on remote sensing). lournal Articles Few artacles deahng with remote sensing related topics have appeared in major Umted States professional geographic journals The authors are not sure how to interpret tins. It may arise partly because of the traditional nature of the arttcles accepted by these journals. Have the edators consciously refused technical articles on remote sensing believing that they are too technlqueonented for their journals? Tins may mdeed be a factor. [In the late 1960s, it
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~,ttendance And Papers Presented By U S Geographers At Remote Sensing Of Enwronment Symposia Held At The Untverstty Of M~chtgan 1962- 1977
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IMPACTS OF REMOTE SENSING
certainly motivated the geographer Edward Rlsley, then a staff member of the National Academy of Sciences, to push for an mterdlsclphnary refereed outlet for remote sensing articles At the hme neither geographic nor other professional journals were very sympathetic to remote sensing articles. Rlsley's discussions with Amencan Elsevier (now Elsewer North Holland) led to the establishment of Remote Sensing Of Enwron-
ment
An
Interdisc~phnary 1ournal ]
Whatever the reasons, geographers generally publish on remote sensing topics outside the chsclpllne. For example, between 1960 and 1976 only seven articles dealing with air-photo lnterpretataon/remote sensing appeared m the Annals of the Association of American Geographers, and three in the Geographical Rewew, whereas 12 articles by geographers appeared in Remote Sensing of Environment and 42 in Photogrammet-
r~c Engineering and Remote Sensing Remote Sensing of Enwronment, which was started w~th Dawd Slmonett as edator and is presently edited by Freeman F. Hall of the Natmnal Oceanic and Atmosphenc Admlmstrahon (NOAA), has served as an outlet for geographers. Pho-
togrammetr~c Engineering and Remote Sensing, the journal of the Amencan Society of Photogrammetry, is one of the most slgmficant single outlet for remote sensing articles written by geographers, and others Texts and Reference Works. It is interesting to note that one important way which geographers have Impacted remote sensing is through pubhcatlon of texts and reference works. The works of Holz (1973) Estes and Senger (1974) Rudd (1974) Lmtz and Simonett (1976) l~chason (1978) and the just published volume e&ted by personnel of the
57
Center for Urban Pohcy Research (Ford, 1979), are evadence of the commitment on the part of geographers to upgra&ng the quahty of information and instruction m remote sensing. The Manual of Remote Sensing published in 1975 provided additional evidence of this (Reeves, 1975), as 2 of the 8 volume editors, 7 of the 51 chapter editors and 35 of the 236 contnbutors to the Manual of Remote Sensing were geographers. On the face of it, these figures appear encouraging On closer scrutiny, however, we are not sure this constatutes research commitment on the part of the geographers, or a lack of it in significant areas by professionals in other disciplines, or to the operahon of an old-boy network among geographers! Research Funding Teaching and pubhcatlon in remote sensing by geographers may be, but are not necessarily associated with advanced research Research on remote sensing topics can be a very expensive undertakang. It is not surprising, therefore, that almost all of the major academic research m geography dealing with remote sensing is funded by agencies of the Federal government. It has essentially been thts federal support which has influenced and created the envaronment for growth in the field of air-photo interpretation/remote sensmg In all &sclphnes At the present time federal funds come mainly from the National Aeronautacs and Space Administration (NASA), either directly from NASA Headquarters or through other federal sources. In addition, various NASA research centers (e.g., Goddard Space Fhght Center, MD, Johnson Spacecraft Center, Houston, TX, and Ames Research Center, Moffett Field, CA) also provide research funds either dtrectly or through various user agencies or groups Other agencies of the
58
Federal government who presently fund geographic research in remote sensing or have provided funds in the past include the Geographic Apphcatlons Program (GAP), of the United States Geological Survey, Earth Resources Observation Systems (EROS) Program, United States Department of the Interior, Office of Naval Research Geography Program, Advanced Research ProJects, Army Engineering Topographic Laboratories, United States Department of Agriculture, the Department of Housing and Urban Development, Department of Transportation through the United States Coast Guard, and the National Oceanographic and Atmospheric Administration, Department of Commerce. Professional Soczety Activities In May 1967, the Association of American Geographers showed interest in remote sensing as a research tool in geography by forming a Commission on the Geographic Apphcataons of Remote Sensing under the direction of James Anderson with Robert Pephes as Executive I)arector An AAG Committee on Remote Sensing was also formed The commission has since ceased to function while the Committee continued to promote educational programs in remote sensing within the dlsclphne through institutes, short summer courses, and workshops. Five short summer courses were sponsored by the National Science Foundation and the Remote Sensing Committee of the AAG to acquaint college level teachers with new remote sensing technology In addition, the Remote Sensing Committee has sponsored remote sensing workshops in connection with AAG's and National Councd for Geographic Education (NCGE) national meetings. More recently the NCGE has also formed a
j E ESTES, J R JENSEN AND D S SIMONETI" g r o u p , This g r o u p in cooperataon w i t h
members of the AAG's remote sensmg committee have been responsible for the workshop at their National meetings The NCGE is also sponsoring the pubhcatlon of a text and workbook on remote sensing (Rlchason, 1978). Attendance at both AAG and NCGE workshops has been excellent and may well be a major factor in stimulating the growth of teaching in remote sensing in geography. Another significant activity of the Remote Sensing Committee of the AAG has been the pubhcation of the newsletter Remote Sensing Quarterly, formally called RSEMS--Remote Sensing of the Electromagnetic Spectrum. Pubhcatlon of RSEMS began in 1974 as a quarterly with a subscription fee of $1 00 per year. The first issues could be characterized by the whimsical motto internally proposed for adoption as the RSEMS logo "Quidman Sesterao Nummo exspectasses" (essentially, "What on earth did you expect for 25e"). As RSEMS has continued, it evolved into a useful, though pnnclpally pedagogac, rather than research quarterly with over 1000 subscribers The editorial staff and guest echtors have concentrated on specific topics (e.g. radar, classroom materials, and laboratory exercises). RSEMS filled a need within geography as an outlet for the smaller research results and as a forum for the exchange of news and ideas. Its improvement over the past four years to a great extent parallels the increasing awareness of geographers to the potential of this tool. With a new editorial staff and active sohcitataon of more substantial research artacles, there is hope that the retltled Remote Sensing Quarterly wall eventually achieve a level of quahty and status equivalent to Geographical Analys~s. The latter is a pub-
IMPACTS OF REMOTE SENSING
hcation which began out of the frustration of quantitative geographers in even finding a voice for thetr research in the traditaonal, essentially antamathematacal antatechmcal geographic U.S. journals in the late 1960's. [This was the same tame as when Remote Sensing of Environment was being established, and for much the same reasons!] Over recent years national meetings of the AAG have increased the number of sessions on remote sensmg, thus drawing geographers away from the nearly coincident Michigan Symposium. There were four sessions on remote sensmg at the AAG National Meetangs in Salt Lake City (1977), five m New Orleans (1978), and several more in Phdadelphia (1979) We confidently expect this level of evident interest and need for appropriate outlets within the &sclphne to contanue to increase Prwate Industry, and Federal, State and Local Government A ctiv~tws Within the period 1962-1977, two rapidly advancing areas of research a n d / o r employment of m&viduals with a background in geographic remote sensing should be mentaoned. These are (1) private mdustry, and (2) state and local governments. The 1967 directory of the Assocmtaon of American Geographers listed 7 geographers in government jobs and 3 m private industry wath a specialty m remote sensing. By 1974, the year of the latest AAG directory, the number of geographers listing a remote sensing specialty had climbed to 43 for government and 36 for private industry. There is every reason to believe that tins rate of ,ncrease is aceeleratang, A complete listing of the industries and goverumel~t agencies where professional geographers with remote sensing interests are em-
59
ployed is beyond the scope of this paper. However, these include such companies as Lockheed Electromcs, Rockwell Internataonal, General Electnc; Earth Satelhte Corporataon, Electromagnetic Systems Laboratory, Spectral Data Corporatlon, Dames and Moore, Henmngson, Durham and Richardson, Tetratech, and others. Within state governments, geographers with remote sensing backgrounds are employed in planmng, environmental protection, and resource development agencies. For example, in Kentucky, then Governor Carrol designated a geographer, Bill Franklin, to serve as his representatave on an Important committee on remote sensing of the National Governors Assocmtion. Federal government geographers wath remote sensing interests are employed in the Bureau of the Census, NASA, Environmental Protection Agency, Geological Survey and Department of the Interlor's EROS Program The Geography Program of the United States Geological Survey is concentratang ItS efforts on land-use analysis and the development of standardized compatible (compatible wath exastlng classificataon systems and with identafiable features as seen on remote sensmg imagery) methods of describing land-use on their new nataonwide 1:100,000 land-use senes. In support of tins nataonwade land-use mapping effort, personnel of (or working for) the Geography Program have pubhshed a wide variety of remote sensing articles including works by' Anderson et al., (1976) on the development of a landuse/land-cover classificalaon system for use with remote sensor data, Anderson (1977) on land-use and land-cover changes and the estabhshment of a
60
j E ESTES, J B IENSEN AND D S SIMONETr
gmmng in the early 1970s, is on the combination of data from different sensors and different times to improve the modehng of complex environmental phenomena. Improvement in both type and quality of input data may potentially be aclueved m many models through the use of spatially-distributed remotely sensed data rather than lumped parameter data. Conventional methods of presenting reformation of vanous areal umts usually assume a homogeneous dastnbution of parameters throughout a data collection unit at a gwen scale. Remotely sensed data, however, offer the p o t e n t i a l to either correctly map or to &saggregate these data and redistribute them m a way which more closely approximates the "real world" chstnbution In adchtlon, due to the time sequential (multitemporal) dimension of data from systems such as the Sun Synchronous Meteorological Satelhte Geostationary Orbiting Environmental Satelhte (SMS/GOES) and Landsat, the time frames over which data can be supphed as drivers for model operation IS also being improved. With the satellites hsted above, data collection for the same geographic locations range from every 30 mln to every 18 days, and although the scales from these satelhte systems vary considerably, the systems presenting higher resolution data may be employed to cahbrate and verify the lower resolution data. Although this type of analysis wdl be chscussed m more detaal later (under the 1972-Present section on functional and ecological sysAlthough the period just chscussed ex- tems analysis), a few comments are aptends through the present, the authors propriate here Dunng the last three or believe a slgn~cant new phase in geo- four years work by geographers which graphic research with remote sensing incorporates remotely sensed data into data has begun. This new emphasis, be- modeling of environmental phenomena framework for monitonng such changes, Alexander et al., (1976) on the apphcations of Skylab data to land-use and chmatologtcal analysis; Ackerman and Alexander (1975) on designing a national land-use information system, Ellefsen et al, (1973) on machine processing of early Landsat data for the derivation of urban land-use reformation; EUefsen et al., (1976) on computer-aided mapping of land-use, Feng et al., (1973) on the development of an operational apphcation of orthophoto mapping techmques for use in a system designed for the detection of change m urban areas, this was preceded by Jim Wray's (1972) work on the cartographic aspects of an operational system for detecting urban change by remote sensing, Dolan and Vincent (1973) on coastal processes, and, Tomhnson et al (1976) on computer handhng of geographic data The October 1977 issue of RSEMS (Vol. 4, Number 4) discusses the work of the Geography Program Other articles by the Program include those by Fltzpatnck-Lms (1978) on accuracy and consistency comparisons of land-use/ land-cover maps complied from high-altitude photographs and Landsat muhlspectral tmagery, Guptill (1978) on optimal filters for maps showing nominal data, and Mitchell et al., (1977) on GIRAS a geographic information retneval and analysis system for handhng landuse and land-cover data
IMPACTS OF REMOTE SENSING
have dealt mmnly wath agricultural and land-use related topics: Land-use/land-cover (Harwood et al, 1977, Wllhams, 1977) 2. Estimates of winter wheat yields (Morton and Wllhams, 1973, 1975). 3 Momtonng of spring wheat production (Slmonett et al., 1974). 4. Agricultural water demand modehng (Tmney et al., 1974, Estes et al., 1975, Jensen et al, 1977; Estes et al., 1978). 5. General crop inventory (Jensen et al., 1975; 1978).
61
2.
1.
3.
4.
1980, Nicholas and Lewis, 1980). Populahon census actwltaes (Chnstenson and Lachowslo, 1977; and General Electric Co., 1977). Slte/specws vegetahon modehng (Strahler et al., 1978, and Woodcock et al., m press). Snowmelt distributed parameter modehng (Dozier, 1979)
A Perspective on the Present Status of Remote Sensing in Geography
As can be seen from the preceding discussion, remote sensing m geography Other areas where geographers are beginnmg to apply remotely sensed data in has made rapid strides. This development a modeling context have begun to ap- has, however, been coupled with some major disappointments. The number of pear These include lnstitutaons offenng courses in remote 1 Hydrologac modehng (Sohn et al., sensing have increased significantly. 1976, Sasso et al., 1977, Baker et al, However, pubhcahon m major reviewed 1975, Holz et al., 1977). journals within geography has lagged and 2. Modeling of phenomena m the urban the share of substantive research camed environment out by geographers in the overall area of (A). Water demand (Jensen et al, remote sensing may even have declmed. 1977). It is perhaps unfair, but may be close to (B). Land-use change and effects (B1the truth, to say that geography today llmgsley and Bryant, 1975; Estes appears to be moving toward a teachmgand Jensen, 1975; Bryant, 1976, only disciphne with respect to remote Bryant and Zobnst, 1977; sensing, relahvely unaffected by major Bowden, 1979, Pease et al., research programs. On the other hand, 1976, 1977). we could suggest that tlus is a transition (C). Distributed parameter energy phase and that as the teaching programs demand modeling (Clayton and take hold, backgrounds tmprove, and Estes, 1979). graduate students become more and (D). Urban chmatology (Pease and more involved sohd geographic research Nichols, 1976, Lewis, 1977, in remote sensing will expand. It can also Lewis et al., 1976). be argued that other disciphnes, proportionately, seem to be influenced less We are also aware of additional stu&es by remote sensing than geography as now underway, or in press, including: shown by the lesser teaching impact We 1. Land-use chmatology (Pease et al., are, however, suspicious of arguments
62
either way, as such arguments are often based on inadequate and potentially biased and misleading surveys Simply stated, at this time, we are not sure whether there is a firm basis for either hand wrlngang or self-congratulations for any disclphne What is the true measure of the impact of a new technology upon a dlsclphne 9 Is it the prohferatlon of new courses~ The amount of research funds acqmred? The number of publications m scholarly journals9 The acceptance of the technology by recognized leaders m the &sclphne or perhaps even more signffacantly outside the dlsclphne9 As seen above, we are unsure of what answers in these areas m e a n We are sure that there has been a significant increase in the number of remote sensing courses taught in geography and that there is a considerable but unrealized potentml for research funding There have been few refereed remote sensing publications within the major geographic journals, whde geographers contanue to contribute to specialized remote sensmg journals. Finally, there appears to be a lack of acceptance and use of the technology by recognized leaders m the field though this is somewhat counterbalanced by the slgmficant number of departments seeking competent jumor faculty in remote sensing as shown by recent professional advertasements Through this mire of confllctang evidence, what measure should we seek Is ~t possible that the true measure of remote sensmgs's impact on geography is dependent upon how well it allows the geographer to more effectively test hypotheses9 What types of hypotheses do geographers work from9 What are the current modes through which geogra-
j E ESTES, J R IENSEN AND D S SIMONETI"
phers analyze chsclpllnary questions? What analysis techmques are best suited to production of data relevant to such hnes of investigations? In addition, do geographers have a perception of remote sensing as a research area where hardware, software purchase, a n d / o r development time is not worth the physical and/or psychological costs of retoohng9 In all of this we should keep in mind that many semor geographers already have a body of data sources and analysis techtuques with which they are comfortable. These sources have served them well and their professional reputations may even be based on their skdl in employang them Why should they change and employ remote sensing data9 If we can begin to answer this question we approach the heart of the problem, truly defimng the real and potential Impacts of remote sensing on the dlsclphne. In an attempt to do so let us first exarmne some basic foundataons of the dlsclphne and then consider the theorettcal and practical role of remote sensing m geography
The Theoretical and Practical Role of Remote Sensing in Geography Geography traces its ongans back to the ancient Greeks. It is said that Herodotus (484-425 B.C.) IS not only the father of history, but of geography as well (Brock, 1965). Herodotus achieved this dastmctlon because he placed tustoncal events wltlun a geographic setting by gavang descnptave topographies of the places where events occurred. Bernhardus Varemus (1622-1650) was among the first to present the structure of geography as a sclenttfic dlsclphne. Varemus proposed a dwlsion between what he termed general and special geography.
IMPACTS OF REMOTE SENSING
General geography deals with physical phenomena for which umversal laws could be formulated whale special geography examines particular areas of regaons of the earth as they derive their character from the interaction of human and physical processes. Although Varenlus presented the structure of geography as a chsclpllne, it was Immanual Kant (1724-1804) who secured its foundations within the framework of the phdosophy of science According to Kant, all knowledge is separable into three categories. (1) one which sorts facts into groups accorchng to the kinds of objects or phenomena studied, e.g., the systematic sciences of botany, geology, etc., (2) another which sorts facts to vaew them m their relationships through time, e.g. the historical sciences, and (3) the study of things as they are assocmted m space, Le. the prownce of geographical science. This Kantmn wew that spatial analysis is the center piece of geographic thinking is frequently presented as the fundamental justification for geography. It is, m fact, one of the major foundations of Rachard Hartshorne's treatise on the Nature of Geography (1939). A number of geographers, on the other hand, regard the Kantian wew as too snnphstie, arguing that each of the chwslons of knowledge can be viewed from each of Kant's three vantage points and that geography, rather than being a basic diwslon of knowledge, is more a method of wewmg and characterizing environmental relationships. David Harvey, m his book Explanation in Geography, suggests that the following six explanatory forms are employed m the discipline:
1. Cognttive descriptions. This may range from srmple, prmaary observa-
63
tions to sophisticated, statements.
2
3
4
descriptive
Morphometrtc analys~s. In some ways, tlus may be regarded as a type of cogmtive description, one revolving a space-time measurement relationslup rather than a property language. Cause-and-effect analysts This is the insistence that cause-and-effect be established m order to explmn the occurrence of environmental distributions. Temporal modes of explanation From causal explanation, it is a short step to causal chmn explanation which stretch back over tame.
5. Functwnal and ecologwal analysts, This is explonng phenomena m terms of the role they play wltiun a partacular social or enwronmental orgamzation. 6. Systems analysis. Tins is the basis for describing whole complexes and structures of activaties. It ~s only a short step from analyzing the function of a partacular phenomena within an orgamzational framework to studyang the structure of that orgamzation as a system of interlockmg parts and processes. One might reasonably ask what Is umque about these? Surely other natural and social scientists employ the same explanatory forms. The authors are aware that there may be debate concerning these forms; nevertheless we accept them here as a statable basis for structunng the remmnmg discussion However, as we perceive a substantial overlap m the SLX explanatory forms, we have taken the liberty to combine them as follows (1) morphometnc analysis, (2) cause and
j E ESTES, J B JENSEN AND D S SIMONETI"
64
effect analysis, (3) temporal analysis, and (4) functional and ecological systems analysis Within each of these aggregated explanatory forms we pose these questaons 1
2
3.
what does remote sensing permit the geographer to do now b e t t e r than he or she has been able to do in the past9 what does remote sensing permit the geographer to do now that he or she w a s u n a b l e to do m the past, and finally~ what may remote sensing enable us to do in the future winch could be of significance to professional and academic geography9 Morphometric Analysts
Geographical research usually requtres measurement to determine the structure and m o r p h o l o g y of p h e n o m e n a Measured attributes of phenomena may be generally classified as being (1) physical properties, (2) spatial (geographical) properties, or (3) temporal properties. In any type of analysts it ts important to obtain quantitative mformataon concernmg these parameters m addition to descnptave evaluation. Remote sensing plays an important role m prowdlng mformataon on the physical properties of phenomena. In particular, an object's energy response sensed in wavelengths or frequencies throughout the electromagnetac spectrum may prowde quant~tatave data on such properties as geometry (size, shape, arrangement, etc ) spectral color or wsual appearance, temperature, chelectnc nature, mols~re content, and organic and inorganic composition. I n s , t u (or trans-
ducer) investigations are typically costly and are site specific, provachng only pomt observation that must be mterpolated to yaeld a geograpincal surface Remote sensing, on the other hand, may provide both point (per picture element) and areal physical property reformation Tins bnngs us to the next topic of discussion, the measurement of spataal (geographical) properties Geographical data may range from simple zn s i t u observation where the spatlal properties are not important, to complex analyses where the properties of phenomena are most significant when viewed m relatson to their spatial association with other phenomena As geographers are pnmanly concerned with the latter type of morphometnc analysis, it is not surprising that the profession contmues to be interested m hard-copy remote sensing imagery or quantlzed digital data m a matrix format which can be reconstructed to yaeld an image for either interpretation or photogrammetnc analysis if desired Such two-dimensional, and with the proper parallax, three-dimensional (stereoscopic) data provides the geographer with a synoptic view of local or regaonal environments often unattainable from m s , t u data collection. To avoid the connotation that remote sensmg ts always supenor to m s , t u m vestlgatlons, consider the blogeographer who, with aenal photography of hts study area unavadable, discovers that the spatlal resolution of Landsat data ts not capable of provl&ng specific information. Nevertheless, the Landsat imagery, although Impractical for the specific task at hand, might still prowde valuable collateral or surrogate reformation that could significantly affect subsequent m-
IMPACTS OF REMOTE SENSING
65
formataon, winch m turn could signifi- obvaous spataal errors m preremote senscantly affect subsequent lnvestagataons. ing maps where rivers, mountain ranges, T h s points out a fundamental character- and even the spatial dimensions of contilstac of remote sensing when apphed to nents were m error. Thus, remote sensing morphometrlc analysis problems. At a wall allow the geographer's large-scale gaven scale it may prowde specific types and small-scale basemaps to become of categorical lnformataon by Itself, or It more accurate. This has been significan be used as a method of stratff3nng cantly affected by the Landsat satelhtes (Le., regaonallzlng) an area for subsequent winch have a semiangle of only 5.76 ° off analysis Using multiple scale images, it is nadir yielding essentially orthographic posmble to stratify regions and design maages. Landsat's plammetnc spatml samphng strategaes wbJch among other fidehty is such that (once it is system-corthmgs may (a) reduce the time and costs rected to ehmmate periodic system assocmted wath samphng, (b) maprove the errors) it meets national map accuracy power of a samphng design through prior standards at a scale of 1.500,000 and m ldent~catlon of appropriate areas (strati- several respects meets 1 250,000 stanfication), (c) reduce the number of sam- dards as well. pies needed to acineve a specified preciCoupled with tins increased capabdlty sion, and (d) slmphfy lnterpretataon. to accurately locate basemap data is the With the understan&ng that classify- very maportant contribution of remote mg phenomena a n d / o r stratafymg homo- sensmg to thematic cartography The geneous regions is an important role for "themes" of data (e.g land use) capable remote sensmg, let us continue to of being extracted from analysis of a evaluate the impact of tins technology's gaven image may be apphed to the previsynoptic, spatially accurate view on geo- ously discussed accurate basemap to imgraphic morphometrlc research. This can prove both the spatial and categorical best be understood by considering the accuracy of the geographer's thematic map, winch is geography's pnnclpal map me(hum for commumcatlng spataal reforAs a result of tins threct impact on mation. Prior to the development of re- basic and thematac map theory, cartogramote sensing, scientific maps were com- phers more than most anticipate the role pded from terrestrial observations. Such remote sensmg may eventually play in maps were only as accurate as the geographic research and education. Tins terrestrial field-of-wew, Instruments, and is because cartographers are reqmred out experience of personnel complhng them. of necessity to understand and utlhze Contrast ths with the present situation remote sensing technology. Consewhere the geographer's basemap, Ins quently, it is not surprising that 38% of maanstay of accurate 2-damenslonal com- the 60 geographers teacinng remote sensmumcation, is for all practical purposes ing m the Umted States m 1976 hsted almost totally derived from a combma- cartography as one of their speclaltaes taon of photogrammetnc and photolnter- (AAG, 1976). Interestingly, in 1977, we pretataon techmques. Koeman (1970) and find cartographers proposing the techmColvocoresses (1975) have pomted out cal parameters for an operational Land-
66
j E ESTES, J R JENSEN AND D S SIMONETI"
sat. In their words, consider the impact of satelhte imagery on spatial (geographical) problems It may seem presumptuous for a cartographer, or group of cartographers, to undertake the task, but the cartographers who would map tius Earth have as great a stake m Landsat as any other dlsclphnary group Geologtsts, agriculturists, foresters, and land use planners, as examples, are equally revolved, but thetr operatmnal use of Landsat depends m no small part on the solutaon of eartograpluc problems These m turn depend on relatave and absolute geometry as well as the mformalaon content of Landsat data There ts probably no other concerned group as demanding as cartographers and, from what we have seen to date, Landsat data when properly processed can meet its demands for the plammetne portrayal of the coarser Earth-surface features (Colvocoresses, 1977)
Stall other evadence of the united wewpolnt of remote sensing specmlists and cartographers is given by the numerous artacles on "image processing" appearing m cartographic journals (Muehrckl, 1972, Monmomer, 1976) and data handling symposia throughout the 1970's (Tomlinson, 1972). In effect, cartographers and remote sensmg specialists understand that whether one deals wath a map or a photograph xs immaterial. The fundamental goal is to produce and communicate the reformation contained in each so a meaningful concluslon can be drawn. Thus, we find both cartographers and remote sensing speciallStS concerned with essentially the same topics First, how to collect information either in the field or with a sensor system; and second, how to interpret and unambiguously communicate the results be it m a map or image format. With so much in common it is understandable that numerous essentially cartographic problems have been addressed and
answered within the realm of remote sensmg research dunng the last decade. Cause-and-Effect Analysis Obwously, the synoptic view just discussed has important lmphcat~ons for regional studies whtch attempt to identify cause-and-effect relationships between phenomena visible on the landscape. The German geographer Alfred Hettner expressed the view in 1898 that "mere description has been replaced m all branches of geography by search for cause" (Hettner, 1898). The estabhshment of cause-and-effect relat~onslups is central to researchers m all branches of scientific endeavor. By employing sensor systems sensitive to electromagnetic energy both within and outside the visible spectrum, it is possible to enhance our capabdlty to determine causation, define causal pnncxples, or enuncmte causal determinism by increasing our abdlty to percewe effects which for a variety of reasons may be beyond our direct visual experience. This may include percewmg a given wavelength of energy outside the wslble spectrum and/or assuming a viewing perspective for a sufficient period of time (e.g., geostatlonary satellite) to adequately momtor phenomena. Man has always perceived the end resuits of processes acting on his surrounding (effects) and attempted rational explanations based on his current level of knowledge, experience, and understanding In his work on the nature of geography, Harshorne devotes considerable attention to a discussion refuting the view that there be a hnutation on geography to things perceived by the senses. In h~s discussion, Hartshorne states that geographers "have long recograzed in prac-
IMPACTS OF REMOTE SENSING
tlCe that, for many of the features that all agree must be studied, we cannot depend upon any direct form of observation." Hartshorne summarized his extended chscusslon of the question of the hmltatlon of geography to areal phenomena which are "in general, visible" by stating that such a view would "d~srupt even a central core of 'pure geography' by placing certain aspects of areas outside of the geographer's field of study, except that he later finds it necessary to investigate them in order to interpret what he has studied." What IS implicit in Hartshorne's discussion is that techniques by which we may expand our perceptions of our environment to permit a deeper, richer understanding are well within the analytic preview of geographers Remote sensing offers the important capability to extend our detection and understanding of effects which were until now basically beyond the hmlts of our perception and effective measurement. For example, a thermal infrared scanner can record temperature differences in a nver to pinpoint the location of a thermal plume undetectable to the unaided human eye Similarly, reflective near-infrared photography has been used to detect biophysical stress (i.e., effect) before the cause (e.g, loss of moisture from pathogens) is detectable in the visible spectrum. In addition, earth synchronous meteorologacal satelhtes in geostationary orbits such as SMS/GOES are just one of any number of satellites providing researchers with synoptic temporal data helpful in the determination of cause and effect relationships which would be unpossible to obtain in any practical sense without the use of remote sensing technology The capability of remote sensing
67
to provide such data demonstrates the expanded potential for the generation of basic source material offered to geographers on topics previously chffieult, if not impossible, through the judicious application of remote sensing technology. In addition to the multispectral attributes present in a gwen cause-and-effect relationship, the ability to perceive the simple geometric shape of phenomena as they progress or regress is tmportant For instance, the geometry of suburban sprawl, insect infestation, flood lnnundatlon, fault related topography, erosion, etc., as they appear on successive synoptic images represent valuable sources of information which may be used to identify cause-and-effect relationships. Without such data the researcher may be seriously handicapped in malong conclusions related to geographic research. This potentaal of remote sensing, however, has stall not been substantively employed by geographers. However, we anticipate that the space systems of the 1980's (Landsat-D, Multispectral Resource Sampler, Magsat, Stereosat, the Space Shuttle, etc.) will offer opportunities for its use. Indeed, because of the lrnproved spectral, spatial, and temporal resolutions expected from the coming space systems, it is incumbent upon geographers to actively use the new data, or isolate themselves from an essential part of the new geography. Other chscIphnes will not allow any inches to remain unoccupied!
Temporal Modes of Explanation Although most geographers would agree that spatial variation IS of prime concern whde history concerns itself with change through time, the geogra-
68
pher cannot ignore the temporal domam nor can the historian chsregard the unphcataons of space. The geographer's concern w~th tame stems from two pnncapal consaderataons. 1. A concern wath the explanataon of observed phenomena, such explanahons typacally mvolve an analysis of processes and sequences whach occur through tame. Typacally explanataons of ttungs observed m the present have roots m the past 2. Change through tame as an maportant charactenstac of place, and vanataons m rates of change of the components of a gaven locataon conshtute an amportant spataal varmble (Hammond and McCullagh, 1974). As Hartshorne states m has chscussaon on "Tmae and Genesas m Geography" m Perspectwe on the Nature of Geography, "To the best of my knowledge, no competent student of the methodology of geography has ever asserted a statac concept or faded to recogmze that the dimensaon of tame as always revolved" (Hartshorne, 1959). "Change" to geographers then, as synonymous with process and sequence. Thus, to be able accurately and consastently to adentafy change m a spataal framework as an amportant part of any morphometnc cause and effect or functaonal and ecologacal systems mvestagataon The capabdity to vaew objects a n d / o r phenomena an their spataal context through tame an a broadly consastent manner as potentaally one of the more amportant contnbutaons of remote sensmg to geography. Inconsastent data sources currently plague temporal stuches. Landsat data, on the other hand, is a reasonably anternally consastent, longatuchnal (i.e., temporal) data set. What are the internally consistent features of Landsat which promote geo-
j E ESTES, J R JENSEN AND D S SlMONETr
graphic (temporal) analysls~ Landsat has been placed m a sun-synchronous orbit so as to trnage the same geographic area once every 18 days (9 days if t w o satelhtes are used) at very nearly the same tame, scale, geometry, look angle, and sensor configuration. Consequently, change of a great dwerslty of phenomena may be assessed rapidly through multadate subtractaon techmques or through rahomg channels of chfferent dates. Here agmn, as satelhte data with tmproved spataal resolutaon generally becomes avadable (e.g, 40-meter Return Beam Vldlcon on Landsat-3 (launched March 1978), 30-meter Thematac Mapper on Landsat-D (to be launched 1981), 15-meter Multaspectral Resource Sampler (to be launched possibly mld-1980's), our abdaty to employ these data to monator the sequence of phenomena whach constatute process wall become even better. In the fnal analysas, the acqtnstaon of single date or multatemporal data depends upon whether the geographer as concerned with statac or dynamac phenomena If he as pnmardy concerned with relatavely statac phenomena (e g, sods, slopes, rock types), single or widely spaced (m a temporal sense) observataons may be sufficient If, on the other hand, he as anterested an dynamac phenomena the temporal resolutaon of the systems chscussed above as Lmprovmg to a pomt that certmn dynamac processes (e.g., runoff, flooding, crop growth, moisture response) may be effectavely modeled w~th an accuracy heretofore unattainable. In addahon, by anterrogatang an mteractaon matrix between statac and dynamac phenomena driven with remote sensmg supphed data, much detailed mformataon concernmg the functaomng of both statac and dynamac elements present
IMPACTS OF REMOTE SENSING
in a given landscape might be achieved. In traditional geographic research, the high-temporal resolution required to drive such models is obtainable only by extensive costly data collection platforms (DCPs) a n d / o r field work As seen in the discussion concermng developments from 1972 to the present, the first remote sensing aided models that attempt to systematically acquire data with a high-temporal resolution are currently being evaluated. With the aid of remote sensing, systematic analysis of multldate change detection for a variety of environmental processes may be possible. By the apphcation of multldate change detection techniques, geographers may be able to quantify the rate and perhaps even the geometry of many processes at work m our environment. Probably the biggest handicap to this type of apphcataon, however, will be the requirement that investigators be famlhar with the imaged data (in either analog or dlgatal formats) to be interfaced with their traditional nonremote sensing data sets (e.g., the census). This topic wdl be addressed m the following section Functional and Ecological Systems Analysis
All the previously discussed roles of remote sensing in geography are involved m systems analysis. It is here that the data must be transformed Into reformation to help make a division or to understand a process While geographers often require spatially accurate data for both mlero- and macroscale phenomena, efficient or accurate methods commonly do not exist for collecting these data. Remote sensing offers some of this needed potential and is beglnmng to be
69
apphed to systems analysis at both ends of the spatial continuum. For instance, the authors, other geographers, and scientists m other ¢hsclphnes with remote sensing backgrounds are exarmnlng the information gained by the apphcatlon of ¢hstnbuted rather than lumped parameter models to a number of physical processes and cultural phenomena (e.g., multacrop inventories, monitoring snowmelt runoff, developing models for momtonng urban expansion, and energy consumption). Although data of varying degrees of completeness are available through conventaonal procedures in these areas, they are used primarily In lumped systems. The use of remote sensing and distributed-parameter models together appears attractive in several ways First, remote sensing data, which is inherently distributed (i.e, spatially dlsaggregated) has proven not easily or inexpensively compatible with exlstang lumped models. The latter are not designed to accommodate remote sensing inputs. Remote sensing data, however, are Intrinsically more compatible with dastrlbuted systems. Second, distributed models, both because of their greater spataal specificlty, and because they frequently are more of the deterministic than of the index type offer the potential of greater forecasting power under extreme conditions Finally, the combination has an especial appeal because to some degree it appears that each needs the other to reahze its maximum contribution Despite these attractive aspects of the eomblnatlon, some cautaon is warranted for several reasons. The substantial inherent difficulties m distributed parameter modehng are now surfacing vcadely (for watershed modehng for example, see Overton and Meadows, 1976, Lmsley,
70
j E ESTES, J R JENSEN AND D S SIMONETr
1976, and Peck, 1976). Even simple in- concerned with water d e m a n d and dex models may skim off the bulk of the stress, (3) agrometeorologlcal models benefits from modehng because of sys- within which remote sensing performs a tem conservahon and averaging. Also the confirmahon, weighting, or cahbratlon reduchon m the uncertainty from that funchon, and (4) descnptive and predlcachieved by index models--through use hve models of land-use change based on of distributed parameter m o d e h n g - - m a y frequent updating. A review of the previous list will reveal be insufficient to warrant the conversion costs and other expenses revolved In hy- a serious gap m the modeling realm. drology, many professionals see remote Other than crop yield, note the senous sensing as being of only shght value m lack of attempts to incorporate remote well-gauged watersheds but do expect ~t sensing into economic modeling. The to be of considerable use in ungauged primary reason for this is that economic geographers have the census available watersheds. A third recent development which which is a first-rate source of informabegs for incorporation of both remote tion Therefore, why be concerned with sensmg data and use of chstnbuted- remote sensing? We suggest that satelhte parameter modehng is that of geobase remote sensing could perform the imreformation systems (Bryant, 1976, portant role of "unpacking" aggregated census data in both space and time For Bryant and Zobnst, 1977; Slmonett et al (eds), 1978, Shelton and Estes, 1979). Un- instance, a researcher may be using a til recently, geobase information systems population density stahstac for a given essentially lacked data of a quahty, quan- census tract wbach is spatml m nature but hty, and hmehness to adequately dnve highly aggregated By incorporating hetthe systems Dependmg on the apphca- erogeneous land-use data derived from tlon, remote sensing may provide data m remote sensing, ~t ~s possible to unpack a format and time framework compatible the census tract data allowing the researcher to know which spatial regions with the range and consistency needed However, there are many difficulties stdl wathm the tract account for most of the be to resolved if the incorporation of vanance. In effect, both the census and remote sensing ~s to have a slgmficant remote sensmg data become calibrated and may be used with change detection impact on geographic systems analysis First, one of the major dlscovenes in and future land-use modeling to provade workang with Landsat data has been that a variety of socml and economic statistics even at ~ts current 80-m spatml resolu- of importance to economic geographers tion, it provides data of such spahal de- In this respect it is important for ecotad and specificity that exlstang models nomic geographers to note that the cannot accommodate the data. Among census itself is presently funding studies the areas where mvestlgators are now to test how the mergang of Landsat and tmprowng existing models to incorporate census data can improve the latter the remote sensing data are (1) hydroThus, we find that remote sensing may logic models incorporating landcover and play an integral part in systems analysis land use data, (2) agricultural models whereto it may funchon as a "hnch pro"
IMPACTS OF REMOTE SENSING
71
At the 1964 conference sponsored by the Nahonal Academy of Science/National Research Councd, (Nahonal Academy of Scwnce Nahonal Research Councd, 1966) Peter Goshng described an "air of enthusiasm which msplred panel members to work eagerly and nnagmatwely on thetr respectwe reports." This meeting brought together at a cntacal early stage m the Umted States space program the talents of a number of chstmgmshed geographers to make recommendahons on the potential of the newly developing field of spacecraft remote sensing as a tool for the geographer Statements at this meeting such as "The opportumty to obtain synophc, regularly repeated vaews of the whole earth and the changang surface of the lands and seas wdl have a profound effect on the growth and mternatlonahzatlon of geographic sciences," dlustrate the potenIn Conclusion: A Look hals recogmzed by these leaders in the at The Future field (National Academy of Science Nahonal Research Councd, 1966). It is a H V. B. Khne, Jr, writing on the pity that more of the attendees did not prospects for air-photo mterpretatmn m mallntaln their enthusmsm! American Geography Inventory and ProThe exploltahon of the improved or spect (m James and Jones, 1954), quotes umque mformatmn avadable to the geogJohn E Kesseh as saying, "Only in de- rapher wa the apphcatmn of remote senspartments so sufficiently staffed to con- ing techmques has barely begun Yet, sider all parts of the geographic field can when thoughtfully analyzed it can be it be expected that air photography has seen to provide the geographer with found, or may find, its due conslderataon slgmficant xmprovements m the quanhty, as a research field" Furthermore, the quahty, and hmehness of data reqmred student " • is mchned to neglect field As more geographers become aware of and laboratory courses which prowde a the slgmficant lmphcatlons of remote training in the gathenng and lnterpreta- sensing for prowchng such data, the true hon of mformahon, hoping that his prob- impact of this techmque m the dlsclphne lem wdl take care of ~tself when the hme wdl be felt Remote sensmg, hke cartogfor Independent research arrives " It is raphy, is approaching such a state of hoped, m geography flus sltuahon is technology and body of coherent knowlchangmg edge and theory that it can almost be
to interface meteorologacal, social, economic, and physical data together for effectwe modehng purposes As previously noted, however, cartographers and physical geographers currently account for the most serious basic and apphed remote sensing research Economic and regional geographers, on the other hand, are largely lguonng remote sensing technology The burden falls heavily, therefore, on those geographers who are cartography/remote sensing technologists to interface wath the regaonal and economic geographers and acquaint mdlwduals m these important areas of the potentmls offered by remote sensing technology. In this manner, our colleagues may begin to incorporate the mformahon derived from the analysis of remotely sensed data into their research.
72 vaewed as a chsciphne m and of itself. What is requtred to increase the tmpact of remote sensing m geography is a concerted effort on the part of geographers and others who speclahze in remote semsng to c o n d u c t their research thoughtfully so as to more effechvely impact thetr dasclphnes. The quanhtatave revolution of the late fifties and stxhes m geography taught geographers to be more ngorous m our approach to data analysis. The remote sensing revolution is now showang a growing number of geographers that we can be more rigorous in our methods of data collection. This is particularly true with respect to the collectaon of data on spatmlly distributed p h e n o m e n a By comblmng advanced data collection procedures Incluchng remote sensing wath rigorous data analysis techmques and employing tins synergasm to the modehng of spatially chstnbuted biophysical and socioeconomic phenomena the true potential of geographical analysis comes closer to reahzahon. Yet, just as the acceptance of the quanhtahve mathematical school of geographical analysis was slow m coming and severely cnhclzed by the "old guard," so too is remote sensing feehng this same type of restraint as we attempt to awaken geographers to Its capablhhes. Remote sensing is a reahty within geography whose tune has come It is too powerful a tool to be ignored in terms of both its information potential and the logic implicit in the reasoning process employed to analyze the data W h e n allied wath the traditional cornerstone of geography, 1 e., cartography, in its new dagatal ratment, the two techmques can go far beyond being mere technologies W e predict they could change our perceptaons, our methods of data analysis,
j E ESTES,j R JENSENAND D S SIMONETF our models, and our paradigms. This process to some extent has already begun on the physlcal/envaronmental side of the ¢hsclphne but the full potential for corssfertdlzmg synergasm which can enrich the whole field of geography wdl be realized only if a larger share of the regtonal, economic, and social geographers make some use of the techmque, and only if geographers aggressively seek the research funchng required to demonstrate the magnitude of the promise held in remote sensing m these areas
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48 Eyton, J R (1979), Interpretahon of Remote Sensing Imagery, Remote Sensmg for Planners, Center for Urban Pohcy Research, Rutgers Umverslty, New Brunswick, NJ pp 19-40 49 Eyton, J R., and Kuether, R P (1978), Macrophotography of Satelhte Images,
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44 1019-1021 50 Bartlett, D S, and Klemas, V (1977), Vanabdaty of wetland reflectance and its effect on automatic categorrzation of satelhte tmagery, Proc Amer Soc Photogram, 43rd Annual Meeting, pp 70-89 51 Klemas, V., Daws, G , Wang, H , Whelan, W., and Tornator, G. (1974), A cost-effective satelhte-alrcraft-drogue approach for studying estuanne clrctdation and shelf waste Chsperslon, Proceedings of the Ocean 75 Conference, San Diego, CA. 52 Kraus, S P, Estes, J E., Atwater, S. G , Jensen, j R, and Vollmers, R R. (1977), Radar detection of surface od shcks,
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IMPACTSOF REMOTESENSING 53 McDonnel, M. J, and Lewis, A J (1978), Ship Detection from Landsat Imagery, Photogram Eng Remote Sens 44 297-301 54 Estes, J. E , Mel, M R, and Hooper, J O (1977), Measuring sod moisture with an atrborne imaging passwe microwave rachometer, Photogram Eng Remote Sens 44 1273-1281 55 Welch, R (1977), Progress m the specfftcataon and analysis of image quahty, Photogram Eng Remote Sens 43 709-719 56 Welch, R., and Lo, C P (1977), Height measurement from satellite images, Photogram Eng Remote Sens 43 1233-1242 57 Tmney, L. R, Jensen, J. R., and Estes, J E (1977), Mapping archeology sites from historical photography, Photogram Eng Remote Sens 43 35-44 58 Thomas, I L, Lewis, A J, and Chmg, N P., Snowfield assessment from Landsat, Photogram Eng Remote Sens 44 493-502. 59 Lewis, A J (1977), Coastal mapping with Radar, G eosci Man, 43 239-247 60 Klemas, V, Bartlett, D, and Rogers, R (1975), Coastal zone elasslficataon from satelhte imagery, Photogram Eng. Remote Sens 41 499-513 61 Seevers, P M, Peterson, R M , Mahoney, D J, Moroney, D G, and Rundqmst, D C (1975), A wetlands inventory of the State of Nebraska using ERTS-1 maagery, Remote Sensing of Earth Resources, Vol 4, Umv of Tenn Space Inst, pp. 281-292. 62 Rehder, J B (1976), Changes m landscape due to strip immng, ERTS-1A New Window on Our Planet, U.S Geological Survey Professional Paper 929, Government Printing Office, Washington, D C, pp 252-257
75 63 Rehder, J. B (1973), Geographic apphcahons of the earth resources technology satelhte (ERTS-1) to landscape changes, Proceedings of the F~rst Pan Amerwan Symposmm on Remote Sensing, Panama and Republic de Panama, Servlclo Geodeslco Interamencano, 1973 (in Enghsh and Spanish), pp 122-131 64 Mower, R. D, and Helnrlch, L. (1977), "A computer processed Landsat land cover map of North Dakota," Remote Sen~ng of Earth Resources, Vol 6, Umv of Tennessee Space Inst, pp 295-307 65 Mower, R D. (1976), Dlscnmlnahon of land and water resources using multispectral remote sensing techmques, Proceedmgs of the Workshop for Entnronmental Apphcat~ons of Mult~spectral Imagery, Ft Belvaor, VA, pp 70-92 66 Walsh, S J (1978), Dff-ferentlahon and mapping of comferous tree specaes through remote sensing techmques, Symposmm Remote Sensing Apphcat~ons m Resource Management, Oklahoma State Umv, Norman, OK 67 Henderson, F M (1977), Land-use mterpretataon with radar unagery, Photogram Eng Remote Sens 43 95-99 68 Comer, J C (1977), Concepts of urban information systems with apphcatlons to India, Nagarlok 9 1-12. 69 Klemas, V., and Leu, K J (1977), Apphcabdlty of Spacecraft Remote Sensing to the Management of Food Resources in Developing Countries, Professional Report Davlslon of Internahonal Programs, Washington, D C., Nataonal Science Foundahon 70 Pannell, C W , and Welch, R (1976), Recent Satelhte Coverage of China, China Geograph 3 21-33 71 Welch, R, and Pannell, C W (1975), Landsat investigations of recent urban land use changes m Northeast Cl~na, Proceedings of the Tenth Intematzonal
76
Symposium on Remote Sensing of Enmronment, ERIM, Ann Arbor, MI, pp 373-382 72 Lo, C P, Pannell, C. W , and Welch, R. (1977), Land use changes and city planrang m Shenyang and Canton, Geograph Rev, 67.268-283 73 Institute of Science and Technology (1963), Remote Sensing of Environment, Final Report, ONR Contract No. NOnr 1224 (4r), 71 pp 74 Holz, R. K (1973), The Surve, llant Sc,ence Remote Sensing of Entnronment, Houghton Mfffhn Pub., Atlanta, 390 pp 75 Estes, J. E , and Senger, L. W (Eds) (1974), Remote Sensing Techmques for Entnronmental Analys,s, Hamdton Pubhslung Company, Santa Barbara, CA, 340 pp 76 Rudd, R D (1974), Remote Sensing A Better Vww, Duxbury Press, North Scltuate, MA, 135 pp 77 Lmtz, J, Sr, and Slmonett, D S. (1976), Remote Sensing of Env,ronment, Ad&son-Wesley Pubhshmg Co., Reading, MA, 694 pp 78 Pachason, B (Ed) (1978), Introduct,on to Remote Sensing, Kendall-Hunt, Clucago, 496 pp. 79 Reeves, R G (Ed m Ctnef) (1975), Manual of Remote Sensing, Amer. Soc. Photogram., Fails Church, VA, 2144 pp. 80 Pdchason (1978), op c,t, footnote 48 81 Ford, K, ed (1979), Remote Sensing for Planners, Center for Urban Pohcy Research, Rutgers Umv., NJ, 219 pp 82 Anderson, J R, Hardy, E E., Roach, J T , and Wltmer, R E (1976), A land use and land cover classffacahon system for use with remote sensor data, U S Geolog Survey Professional Paper, 26 pp 83 Anderson, J R (1977), l_and use and land cover changes--A framework for momtonng, J Research U.S Geolog. Survey 5 142-152
J E ESTES, J R JENSEN AND D S SIMONETF
84 Alexander, R H , Lewis, J. E., Jr., Ians, H. F , Jr, Jenner, c B, Outcalt, S. I., and Pease, R W (1976), Apphcatlons of Skylab data to land use and chmatological analysis, U S Geol Survey Final Report, 210 pp. 85 Ackerman, E A and Alexander, R. H (1975), Central Atlanhc regional ecological test site (CARETS) Project, Vol 3, "Toward a Nataonal Land Use Informataon system", NASA Goddard Space Fhght Center, Type III Final Report, 68 PP 86 EUefsen, R, Swam, P, and Wray, J (1973), Urban land-use mappmg by machine processing of ERTS-1 mulhspectral data A San Francmco Bay Area example," presented at Conference on Machine Processing of Remotely Sensed Data, Purdue Umverslty, Purdue, IN, 16 PP 87 EUefsen, R, Gaydos, L, and Wray, J. R. (1976), Computer-aided mapping of land use, U.S Geolog. Survey Professmnal Paper, ERTS-1 A New Window on Our Plant, op cst, pp 234-242. 88 Feng, J. S., EUefsen, R, Peruzzl, D., and Wray, J. R. (1973), An operahonal apphcataon of orthophotomappmg in a system of urban change detechon An example from the San Francisco Bay region, U S Geolog. Survey techmcal report, Proceedings of the Orthophoto Workshop II, Amer Soc Photogram. and the American Congress on Surveymg and Mapping, 8 pp. 89 Wray, J R (1972), Cartographic aspects of an operalaonal system for detecting urban change by remote sensing, U.S. Geolog. Survey Professional Paper, Geographic Apphcahons 90 Dolan, R, and Vincent, L (1973), Coastal processes, Photogram Eng 39 255-260 91 Tomhnson, R F., Calkms, H W., and Marble, D F (1976), Computer Han-
77
IMPACTS OF REMOTE SENSING
dhng of Geographical Data, The UN92
93
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95
ESCO Press, Pans, 214 pp Fltzpatnck-Lms, K (1978) Accuracy and consistency compansons of land use and land cover maps made from haghaltitude photographs and Landsat mullaspectral maagery, ] R e s . U S Geolog. Survey 6 23-40 Guptdl, S C (1978), An "optmaal" filter for maps showing nominal data, I R e s . U S Geolog Survey 6 161-167 M~tchell, W B, Guptdl, S. C., Anderson, K E , Fegeas, R G., and HaUam, C. A (1977), GIRAS A geographm information retnval and analysis system for handling land use and land cover data, U S Geolog Survey Professional Paper # 1059 Wdhams, D L. (1977), Ecosystems Map-
pmg by Interpretation of Landscapes from Satelhte Imagery, Ph D. Dlssertataon, Dept of Geography, Umv of Kansas 96 Harwood, P, Finley, R, McCulloch, S., Mahn, P A., Schell, J. (1977), Development and apphcataon of operational teehmques for the inventory and momtormg of resources and uses for the Texas coastal zone, Final report, Goddard Space Fhght Center, Greenbelt, MD, Vol 1, 237 pp. 97 Moram, S A, and Wdlmms, D L (1973), Esttmates of winter wheat yaeld from ERTS-1, Proceedings of the Third
Earth Resources Technology-1 Satelhte Symposium, Waslungton, D C., NASA, Goddard Space Fhght Center, pp. 21-28 98 Morton, S A, and Wdhams, D L (1975), Wheat production estamates using satelhte images, Agron J. 67 361-364 99 Stmonett, D. S., Hord, M., Conte, D , Shotwell, R, and Haynes, J (1974), An mvestagataon of the feaslbrhty of developm g a serm-automated system for morn-
tormg spnng wheat produclaon, Earth Satelhte Corp., Sdver Springs, MD, U.S Dept of Agriculture, Contract No. 12341034, pp 1-362, 1974 100 Tmney, L R., Estes, J E., Thaman, K H., and Thaman, R R (1974), Operataonal use of satelhte and high altatude remote sensing for the generatton of input data for water demand models, Pro-
ceedings of the Nmth Sympostum on Remote Sensing of Envtronment, Ann Arbor, MI, pp 739-757 101 Estes, J. E., Jensen, J R, and Tmney, L R (1975), Remote sensmg Inputs to water demand modehng, Fourth NASA
Earth Resource Survey Sympostum, Houston, TX, pp 2585-2620. 102 Jensen, j R., Estes, J E , Bowden, L, and Tmney, L R (1977), Remote sensing of water demand mformataon, Geograp Rev., July, 1977, pp. 322-334 103 Estes, J E , Jensen, J R, and Tmney, L. R. (1978), Remote sensing of agricultural water demand mformataon A Cahforma study, Water Resources Res , 14 170-176 104 Jensen, J R, Tmney, L R., and Estes, J E (1975), An analysis of the accuracy and cost-effectaveness of a cropland inventory utdlzlng remote sensing techmques, Proceedings of the lOth Sym-
postum on Remote Sensing of Enmronmerit, ERIM, Ann Arbor, MI pp 1149-1158 105 Jensen, J. R., Estes, J. E , and Tmney, L R. (1978), H~gh altatude versus Landsat nnagery for chgttal crop ldentaficataon,
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44 723-733 106 Sohn, R L, Becker, L., Estes, J E , Slmonett, D S., Yeh, W (1976), Analysis of Information Systems for Hydropower Operations, Jet Propulsion laboratory, Pasadena, CA, RTOP 77-30, 01 107 Sasso, R R, Jensen, J R, and Estes, J E (1977), Automatac tmage proeessmg of
78 Landsat II chgatal data for watershed runoff pre&ctaon, Proceedings of the Eleventh Symposmm on Remote Sensing of Enmronment, ERIM, Ann Arbor, MI pp 591-600 108 Baker, V R, Holz, R K, Hulke, S D., Patton, P. C., and Orrellana-Penteado, M M (1975), Stream network analysis and geomorptuc flood plato mapping from orbital and suborbital remote sensing imagery, Apphcatlon of flood hazard studies m central Texas, Final Project Report for NASA, EREP, no. 064B 109 Holz, R K, Baker, V. R., Sutton, S., Jr., and Orellana-Penteado, M M (1977), An Analysm of South American Rwer Morphology and Hydrology from ASTP Imagery, prolect report submitted to Smlthsoman Inst 110 Jensen, Estes, Bowden, and Tinney (1975), op c~t 111 Bdhngsley, F. C, and Bryant, N A (1975), Design criteria for a multaple mput land use system, Procee&ngs of the NASA Earth Resources Survey Symposture, Houston, TX, NASA TM X58186, Vol I-V, pp 1389-1396 112 Estes, J E and Jensen, J. R (1975), "A remote sensor's view of some aspects of user-remote sensor-cartographic interface commumcalaon problem, Proceedrags of the Cartographw-Remote Sermng Interface m Land Use Data Acquisition and Presentatum, Dept of Geography, State Umv of New York, Albany, pp 12-37 113 Bryant, N L (1976), Interpretataon of socioeconomic data and remotely sensed imagery for land use apphcataons, Proceedings of the Caltech /1PL Conference on Image Procesmng Technology, Data Sources and Software for Commercial and Scwnt~fw Apphcat~ons, Calff Inst Technology, Pasadena, CA, No 3, pp. 9-1 to 9-8 114 Bryant, N L. and Zobnst, A L (1977),
J E ESTES,J B JENSENAND D S SIMONETF
115
116
117
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119
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An image based mformatlon system, architecture for correlatang satelhte and topological data bases, Proceedings to the Advanced Study Symposmm on Topologwal Data Structures for Geographw Information Systems, Harvard Umv, Center for Computer Graphics, Cambridge, MA Bowden, L W (1979), Using Remote Sensing for Planmng Applications, Remote Sensing for Planners, pp 55-58 K Ford (Ed.), Center for Urban Pohcy Research, Rutgers Umv, New Brunswick, NJ pp 55-58 Pease, R W , Lewis, J E , and Outcalt, S I (1976), Urban terrain chmatology and remote sensing, Ann. Assoc Amer Geograph 66 557-569 Pease, R, Jenner, C, and Lewis, J E (1977), Methods for analysis of the impact of land-use change on clLmate RSEMS 4 126-141 Clayton, C and Estes, J E (1979), Distributed parameter modehng of urban energy demand for special issue on mformataon systems, N L Bryant, (Ed) Remote Sens Q 1 106-115. Pease, R W and Nichols, D A (1976), Energy balance maps from remotely sensed imagery, Photogram Eng Remote Sens 42 1367-1373 Lewis, J E. (1977), Research m urban chmate at McGlll Umverslty, Chmatolog Bull 22 11-18 Lewis, J E, Outcalt, S I, and Pease, R (1976), Verifying an urban surface climate slmulatton model, Proceedings of the Symposmm on ModeUmg ChmatePlants-Sods, Land Resources Scwnces, Umversity of Guelph, April 20-21, p. 64-75. Pease, R, Jenner, C, and l_~wls, J E (1980), Land use chmatology--A Skylab experience, to appear m U.S Geolog Survey Professional Paper, 1099-A, Land Use Clmaatology 40 pp
79
IMPACTS OF REMOTE SENSING
123 Nicholas, F , and Lewis, J E. (1980), Relationship between aerodynamic roughness and land use, to appear m U S Geolog. Survey Professional Paper, 1099-C, Land Use Chmatology 36 pp. 124 Chnstenson, J w , and Lachowskl, H M (1977), Urban area dehneataon and detectaon of change along the urban-rural boundary as denved from Landsat dlgatal data, Goddard Space Fhght Center, Greenbelt, MD, October, 1977 125 General Electric Company (1977), Preh m m a r y design reqmrements for census/urbanized area apphcataon systems venficataon and transfer, Final Report, NAS5-23412, June 126 Strahler, A H., Logan, T L, and Bryant, N A. (1978), Improving forest cover classification accuracy from Landsat by meorporatang topograpbac mformataon, Proceedings of the Twelfth
Internatwnal Symposmm on Remote Sensing of Envtronment, ERIM, Ann Arbor, MI, pp. 927-942 127 Woodcock, C. E , Strahler, A H., and Logan, T L (in press), Stratrficataon of forest vegetataon for ttmber inventory using Landsat and collateral data, Pro-
ceedings of the Fourteenth International Symposium on Remote Sensing of Enviroument, ERIM, Ann Arbor, MI. 128 Dozier, J. (1979), A solar rachataon model for a snow surface m mountainous terram, Pro& Modeling of Snow Cover Runoff, U.S. Army Cold Regaons Research and Enganeenng Lab., Hanover, NH, pp. 144-153 129 Brock, J O. M (1965), Geography Its Scope and Sptrtt, Bobs Merrdl Press, Columbus, OH 130 Hartshorne, R. (1939), The Nature of
Geography A Crtttcal Survey of Current Thought m the Light of the Past, Lancaster, PA, Assoc Amer Geograph., (reprmted 1961), 504 pp 131 Harvey, op. ctt, footnote 2.
132 Koeman, Cornehs (1970), The Impact of photography from space on small-scale and atlas cartography, Interaat~onal Yearbook of Cartography, Vol. X, pp. 35-39 133 Colvoeoresses, A P (1975), Evaluataon of the cartograpluc apphcataon of ERTS1 tmagery, The Amertcan Cartographer, Vol. II, No 1, pp 5-18 134 Assocmt~on of American Geographers (1974), Directory, Washmgton, D C 135 Colvoeoresses, A P. (1977), "Proposed parameters for an operataonal Landsat",
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43 1139-1145 136 Muehrcka, P (1972), Thematw Cartography, (see, especmUy, chapter 4 on Image Processing), Assoc Amer Geograph., Washington, D C, pp. 53-62 137 Monmomer, M. S (1976), Maps, Distortion and Meanmg, Assoc Amer Geograph., Waslungton, D C. 138 Tomhnson, R F (Ed) (1972), Geographtcal Data Handhng, Vol I and II, Ottawa, IGU Commrsslon on Geograpbacal Data Sensing and Processing, 1281 PP. 139 Hettner, A. (1898), Dae Entwacklung der Geograplue lm 19. Jahrhundert, Geograph Zettsch IV 305-320 140 Hartshorne, op cit 141 Hammond, R, and McCullagh, P (1974), Quantttauve Techntques m Geography, Clarendon Press, Oxford, p 70 142 Hartshorne, R (1959), Perspectwe on the Nature of Geography, Rand McNally and Company, Clucago, p 82 143 Overton, D E and Meadows, M E (1976), Stormwater Modehng, Academic Press, New York 144 Lmsley, R K (1976), Representatave and Experimental B a s i n s - - W h e r e Next~, Hydrol Sct. Bull, Vol 21, No 4. 145 Peck, E L (1976), Catchment Modeling and Imtml Parameter Esttmataon for the
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80
Nalaonal Weather Serrate Paver Forecast System, NOAA Tech Memo NWS. Hy-
base Informatwn Systems Impacts on Space Image Formats, SBRSU Techmcal
dro-31
Report No. 3, Umv of Cahfornm, Santa Barbara.
146 Bryant, N L. (1976), Interpretahon of socioeconomic data and remotely sensed imagery for land use apphcataons, Pro-
ceedmgs of the Cal Tech/IeL Conference on Image Processing Technology, Data Sources and Software for Commercial and Scwnt~fic Applications, Cahf Inst Technology, Pasadena, CA, No 3, pp. 9-1 to 9-8 147 Bryant, N L. and Zobnst, A L (1977), An image based mformataon system, Architecture for correlating satelhte and topological data bases, Proceedings of
the Advanced Study Symposium on Topological Data Structures for Geographic Information Systems, Harvard
149 Shelton, R L and Estes, J E (1979), Integrahon of remote sensing and geograplnc mformataon systems, Proceedings
of the Thirteenth Internaaonal Symposture on Remote Sensing of Enmronment, ERIM, 463-484
Ann Arbor,
MI
pp
150 James, P E and Jones, C F. (Eds.) (1954), American Geography Inventory and Prospect, New York Syracuse Umv Press, 590 pp. 151 Nataonal Academy of Science Nataonal Research Councd (1967), Spacecraft In Geographic Research, Washmgton, D.C, NAS/NRC.
Umv, Center for Computer Graphics, Cambridge, MA 148 Slmonett, D S. et al (Eds), (1978), Geo-
Rece,t~114 September1979.remsed18 Mar1980
43
Impacts of Remote Sensing on U.S. Geography
JOHN E. ESTES, Department of Geography, Unwersttyof California, Santa Barbara, California 93108
JOHNa JVNSEN, Departnwnt of Geography, Umversttyof Gecrtg~ Athens, Georgia30610
and DAVID S SIMONETT Department of Geography, Universityof Caltfom~ Santa Barbara, California 93108
Tim paper exarmnes some tmpacts of remote sensmg on geography As geographers revolved m tim new technology, we revtew and place in context its development, and with a vmon of zts value to our chsc~pime, we are concerned at Its modest unpact on major research areas in geography Even acknowledging that, m a broader vaew, remote sensmg's LmpaCt on geography has been greater than m other disciphnes does not allevmte our concerns that few semor acadennc geographers have remote sensmg research underway, that few economic geographers have exammed its potential, that even fewer regional geographers wtth interests m less-developed countries have remote sensing research interests, and that although there has been growth m the number of remote sensing courses taught in geography, tim has not been accompamed by pubhcaUon m reviewed geograpluc Journals We ask the questaons. What does remote sensing Pernut the geographer to do better a n d / o r cheaper than he or she could do m the past? What may remote sensing enable future geographers to do wluch would be sagndicant to professaonal and academtc geography? We then find that the exploitalaon of the unproved or umque mforn~tmn avadable to the geographer wa the apphcation of remote sonsmg techmques has barely begun Yet, remote sensing ts a reahty within geography whose tune has come It ts too powerftd a tool to be ignored m terms of both its mformalaon l~tenttal and the logic tmphcit m the reasoning process employed to analyze the data We pre&ct xt could change our Perceplaons. our methods of data analysts, our models, and our paradagrns
Introduction Tlus paper examines some of the impacts of remote s e n s m g - - a relatively new t e c h n o l o g y - - o n geography, a dasclplme which traces its origins back to the beginning of learmng. As geographers deeply revolved in this new technology and with a vision of Its future value to our daselphne, we are concerned at its relatavely modest impact on some major research areas in the chsclphne Even ac©Elsevier North Holland Inc. 1980 52 Vanderbdt Ave. New York, NY 10017
knowledglng that m a broader view of t h i n g s r e m o t e sensmg's impact on geography has been as great or greater than m other &sclphnes does not alleviate our concerns over the following. (1) few semor academics in geography have research underway m remote sensing, (2) few economic geographers, who conshtute a sizable body of geograplucally trained professionals, have examined, or have reahzed the potentaal of remote sensmg, (3) even fewer regional geogra0034-4257/80/0~1043 +38501 75
44
phers (notable among them are those with teaching a n d / o r research interests in the less developed countnes) have remote sensing as a professlonal research interest, and (4) although there has been a growth in the number of remote sensing related courses offered by geography departments, this has not been accompained by an increase m research publlcatlon in rewewed geographic journals In the followmg pages, these concerns are exammed, along with a number of encouraging signs such as the relatave strength of remote sensing among physical geographers and especially among cartographers Indeed, there are a number of simdantles between the growth of cartography within the chsclphne and the growth of remote sensmg From an academic/institutional standpoint cartography has made tremendous stndes since the 1950s whde remote sensing appears to have begun similar expansion m the mld-1960s. To set the stage for the dascusslons which follow, a brief history of remote sensing within geography is put forth The current status of remote sensing within the profession is then exarmned with primary emphasis on academm and to a lesser degree on the government and private sectors. The paper concludes with an extended chscusslon of the abdlty of remotely sensed data to prowde reformation witinn the context of the explanatory forms typically used by geographers (Harvey, 1969). Tins is accomphshed within a framework of the questions. (1) What does remote sensing permit the geographer to do now better and~or cheaper than he or she was able to do m the past? (2) What does remote sensing permit the geographer to do now that he or she was unable to do in the pastg, and
j E ESTES, J B JENSEN AND D S SIMONETr
(3) What may remote sensing enable geographers to do m the future winch could be of slgnLFlcance to professional and academic geography? T h e Past In Perspective
The Instoncal development of aenal photographic mterpretataon (later remote senlsng) within geography has gone through a number of stages as suggested In part by Stone (1974)' 1.
.
.
.
.
From 1858 to about 1930 there was very slow recognition that the first photographs taken from the air had utility for mapping. Near the end of this period, experimental use of air photos began in oval enganeenng, forestry, soft conservation, and mapping apphcataons. These later developments coupled with rapid wartime development of air-photo interpretation as a sophisticated lntelhgence gathenng technique form the basis for a second period (1920-1950). A period of technique refinement developed during the transition from wartime to peacetmae (1950-1962). A brief phase with pnmary emphasis on the a p p l i c a t i o n s of air-photo interpretation to geographic problems (1955-1962). The adjustment of these apphcatlons to the expansion of data gathering and analysis into nonvisible regaons of the electromagnetic spectrum (1962 to present). Finally, a period winch is just beganning, in which lnformataon from a variety of platforms, systems, times, and scales are analyzed and used as malor sources of data for modehng
IMPACTS OF REMOTE SENSING
complex enwronmental phenomena (1972 to present). As can be seen from the tame spans associated with these stages, there is overlap. This to be expected within the dlsclphne since development, acceptance, and apphcatlon are not mdependent
To 1930
Although aerial photography had been avadable for some 40 years, it was near the beglnmng of the Twentieth Century when geographers in the Umted States began to reahze the potential of mr photos as an md to geographic research. Dunng World War I, geographers m mdltary units began to see slgmficant peacehme uses for this early nnhtary coverage The first major geographic pubhcatlon on the subject in the Umted States was the American Geographical Society's Special Pubhcataon No. 4, The Face of the Earth as Seen from the Air, by Wdhs T Lee, pubhshed in 1922. This book introduced American geographers to the concept of vaewlng "farmhar scenes from a new angle," 1 e , the aerial perspective Other pioneering works of the period include Joerg's "The Use of Atrplane Photography m City Geography" (1923) and Johnson and Platt's Peru from the Air (1930). In the 1920's, aerial photography in the Umted States was acqmred for topographic mapping purposes. Interpreters working with these photos stressed the cartographic aspects of the coverage. As this work progressed, realization of the topographic and geographic (particularly agricultural) reformation content of these data led to the long-term program of photographing the
45
entire Umted States at regular intervals begmnmg about 1930. 1920-1950
The plan to photograph the whole nation lnltaally had two primary objectives. First was the goal of conducting mechum-scale topographic mapping of the whole nation. The second objectave was the large-scale mappmg of agricultural areas for government subsidy payments which were based on the field acreage of farms revolved xn crop payment programs. Interestangly, as the Department of Agriculture obtmned additional coverage, few geographers experimented vclth the photographs Roscoe (1960) attributed this early reluctance of the geographic commumty to (1) a lack of training in mterpretataon techmques and the relatwe difficulty of acqmnng copies of photo coverage, (2) the mtdtlple objectives of geographic mvestagatlon and the fact that some geographers avoided the use of aerial photos because they could not Identify all objects imaged m a scene, and, (3) the lack of commercial demand for the geographer's mterpreted product. It is probable, however, that some of this lack of appllcataon reflected changes m the basic objectives of American geography. The formerly strong emphases on physical geography were weakemng in favor of more culturally oriented man-land relations (Stone, 1974). 197.0-1950
During World War II, mr-photo interpretation came into its own as an mtelhgence gathering technique. Geographers, both foreign and domestac, were trained as photo interpreters. Interpretation was
J E ESTES, J n JENSEN AND D S SIMONETr
46
accomplished at two levels, tactical and strategic. Emphasis was placed on the preparation and use of "keys" by which Identfflcahon of items of mthtary mgnLflcance could be made rapidly regardless of an interpreter's prevaous experience This wartime exposure prowded excellent training, quahfylng many geographers for peacetime apphcatmns and instruction American geographers experimented wath aerial photography wath regard to both systematic topics and areal differentiation. Geographers began to take photos to the field trying to determine causes of observable chfferences in texture and tone An early artacle by Russell et al. (1943) is a classic dlustration of the use of aenal photography for overall inventory The analysis of mr photos for small-scale geographic studies also continued (Bach, 1942, Light, 1944). In
addition, an arhcle by Stone (1948) on Alaskan vegetation keys provided an excellent example of the value of smallscale coverage (1 35,000 to 1 50,000) for land classification. However, by the end of the period, the pnncipal geographical articles pubhshed in the United States were stdl largely general and descnphve (Cads, 1947, Long, 1947, Stokes, 1950, Foster, 1951, Kohn, 1951, Kesseh, 1952, MacFadden, 1952). 1950-1960
This penod saw the expansion of aerial photographic interpretation in college geography curricula and a rapid diversification of techniques and instrtunentation By 1950, some 13 geography departments, all east of the Mississippi Raver, offered courses in aerial photographic interpretation (Fig. 1) The main con-
Inshtutuons Offering Geography Courses nn Anrphoto Interpretahon 1950- 51
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47
centratlon of these schools was I n t h e northeastern United States, from Ilhnols and Wisconsin m the west to Massachusetts m the east A small discontinuous concentrahon existed m the south w~th courses taught in Lomslana, Alabama, and Georgaa (Schwendeman, 1951) By 1960, the number of restitutions offenng courses in aerial photographic Interpretation had grown to 25 (Fig 2) The pattern in 1960-1961 indicates defimte geographical shifts with schools on the Pacific Coast as well as in Colorado and Utah offenng new courses and some mshtuhons in the Northeast no longer represented (Schwendeman, 1961). In 1960, of the 25 lnshtutlons teaching aerml-photographlc lnterpretahon, 20 offered graduate degree programs m geography (see Table 1)
Dunng th~s time, geographers were stdl working on the development of interpretation keys for physical and cultural dements of the landscape (Black, 1955; Levels, 1957, Kedar, 1959) Some mvestlgahons of the potentml of automated image analys~s were also ~mtaated (Latham, 1959) In general, it is safe to say that most work of the period was overly optlm~shc in spite of occasional warnings (Stone, 1974) Also, geographical writings on problems employing airphoto interpretation techmques dtmng this time were still pnmardy descnphve and lacked thorough penetrating analysis (Stone, 1954, Stone, 1956, Kline, 1954). 1955-1962
Beginning about 1955, emphasis in geographic works using aerial photography
Inst=tut=ons Offering Geography Courses m A=rphoto lnterpretat=on 1960 - 61
I \
' "
"
'
L_
.-
•
!
•
-'"
L .... ",
~
:'r
0 ,o=o,o to
_ ~ 4
, * . ,
,,.t
OraOoa,o ~
ooo
o', o',
~-o~" ~
o
Gr~
note Undergraduate and Graduate refer to departmental status only
FIGURE 2
EAGI73revCEDI77
48
J E ESTES, J B JENSEN AND D S SIMONETF TABLE 1 Inslatutmm with Geography Offenngs m Au'photo Interpretation/Remote Sen~n~ STATE
N ~ m OF Umvr.nsITY
Alabama
Umv of Alabama, Tuscaloosa
Arizona
Arizona State Umv, Tempe N Arizona Umv, Flagstaff Umv of Arizona, Tucson
Cahforma
Cahforma State Umv, Chteo Cahforma State Umv, Dommguez Cahforma State Umv, Fresno Caldorma State Umv, Fullerton Cahforma State Umv, Hayward Cahforma State Umv, Los Angeles Cahforma State Umv, Northndge Cahforma State Umv, San Dxego Cahforma State Umv, San Jose Humbolt State Umv, Arcata Sonoma State College, Rohnert Park Umv of Cahforma, Daws Umv of Cahforma, Los Angeles Umv of Cahforn~ Paversnde Umv of Cahfornla, Santa Barbara
Colorado
1950-1951
1960-1961
1971-1972
1975-1976
O
O
•
•
•
• A •
O
[] •
• [] • 0
•
• •
• •
• •
• • A •
•
0 • • • •
•
A 0 [] • • •
Central Connecticut State College, New Bntam
0
0
Delaware
Umv of Delaware, Newark
•
•
DC
Cathohc Umv of America
•
•
Flonda
~ o n d a A ~ n b e Umv, Boca Baton Flonda State Umv, Tallahass~ Rolhns College, Wmter Park Umv of Flonda, Gameswlle
• •
• •
Conneetaeut
Adams State College, Alamosa S Colorado State College, Pueblo U S Atr Force Academy, Colorado Springs Umv of Colorado, Boulder Umv of Colorado, Denver Umv of Denver, Denver
0 • • • []
•
•
O •
•
•
• A
Georgia
Umv of Georg~ Athens W Georgia College, Carrohton
Hawaii
Umv of Hawan, Honolulu
•
•
Idaho
Umv of Idaho, Moscow
A
A
mmms
Augustana College, Rock l~land Illmms State Umv, Normal N E Ilhnots Umv, Clucago Northern mmms Umv, DeKalb Northwestern Umv, Evanston S Illmms Umv, Carbondale S Illinois Umv, Edwardsvdle Umv of Ilhnots, Urbana W Hhno~ Umv, Macemb
Ind,ana
Anderson College, Anderson Ball State Umv, Munc~e Indmna State Umv, Terre Haute
0
•
• • •
A • • •
• • •
• •
• •
• • •
• •
•
•
•
IMPACTS OF REMOTE SENSING STAT~
NAME OF UmVEBSIT'Z Induma Umv, Bloomm~on Induma Umv, S E , Jefferson Induma Umv, New Mbany
49 1950-1951
1960-1961
1971-1972
1975-1976
•
•
• •
• O
Iowa
Umv of Northern Iowa, Cedar Falls
Kansas
Umv of Kansas, Lawrence Wichita State Umv, Wlcbata
• O
• O
Kentucky
Eastern Kentucky Umv, Pachmond Umv of Kentucky, Lexington Umv of I.~msvdle, Lomsvdle Western Kentucky Umv, Bowling Green
• • O
• • O
•
•
•
• A O O
•
• O •
LonlgLana
Lomsmna State Umv, Baton Rouge Loo~qmna State Umv, Shreveport Nleho~ State Umv, T~bodaux Southern Umv, Baton Rouge
Maryland
Frostburg State College, Frostburg Towson State College, Towson Umv of M a ~ n ~ College Park
Massachusetts
Boston Umv, Boston Clark Umv, Worcester Fitchburg State Cofiege, Fitchburg Frammgham State College, Frammgham
•
•
•
•
• • •
• • O O
•
• • 0 •
O • •
• 0 • •
Mtsstss~ppl State Umv, Mtss~sappl Umv of S Mlsslssapph Hathesburg
•
• •
Montana
Montana State Umv, Bozeman Umv of Montana, Mmsoula
• •
Nebraska
Umv of Nebraska, Lincoln Umv of Nebraska, Omaha
Nevada
Umv of Nevada, Las Vegas
Mlehagan
Mmn~ota
Mms3ssippl
Central Machtgan Umv, Mt Pleasant Mle~gan State Umv, East Lansmg Northern IVhchtgan Umv, Marquette Western Michigan Umv, Kalamazoo
•
Mankato State Umv, Mankato Moorhead State College, Moorhead St Cloud State College, St Cloud Umv of M m n ~ o ~ M m n ~ p o ~
•
• • []
New Hampslure Dartmouth College, Hanover New Jersey
Princeton Umv, Pnnceton Rutgers Umv, New Brunswaek
New Me~aco
New Mexico State Umv, Las Cruces Umv of New Me~aco, Alburquerque
New York
Bnarchff College, Bnarchff Manor Columbm Umv, New York Hunter College, New York State Umv of New York, Albany State Umv of New York, Bmghamton
• •
A
A
0 •
•
•
0 •
• • •
[] • O • •
50
J E ESTES, J R JENSEN AND D S SIMONETT STATE
NAMEoF UmVeSSITY
1950--1951 1960--1961 1971--1972 1975-1976
State Umv of New York, Plattsburgh State Umv College, Buffalo State Umv College, Cortland State Umv College, New Paltz State Umv College, Oneonta Syracuse Umv, Syracuse
0 0
A 0
North Carohna Appalachan State Umv, Boone East Carohna Umv, Greenvdle Umv of N Carolina, Chapel I-Idl Umv of N Carolina, Charlotte North Dakota
Umv of North Dakota, Grand Forks
Oho
Bowling Green State Umv, Bowlmg Green Kent State Umv, Kent Mmrm Umv, Oxford Mu_qkmgumCollege, New Concord Oho Umv, Athens Umv of Akron, Akron Wittenberg Umv, Springfield Wnght State Umv, Dayton
0
0 0 0
0
@
0
Oklahoma
East Central State College, Ada Umv of Oklahoma, Norman
0 B
0
Oregon
Oregon State Unlv, Corvahs Portland State Umv, Portland Umv of Oregon, Eugene
0
O
Pennsylvania
Indmnu Univ.of,Penn,, Ivdtana Lock Haven State C611e~e, Lock Haven PennsylvaniaState Univ., State Q~llege Temple Univ, Phdadelphta Umv of Ptttsbur~ lhttsburg
O
South Carolina Univ. of South Carolina, Columbm South Dakota
South Dakota State Univ, Brooklings
Tennessee
East Tenn State Untv, Johnson City Memphis State Umv., Memphis Umv of Tennessee, Knoxvdle
Texas
North Texas State Umv, Denton SW Texas State Univ, San Marcos Umv of Texas, Austm
Utah
Brigham YoungUmv,, Provo Umv of Utah,'Sa]t Lake City Weber State College, Ogden
[]
0 A
0
0 0
Vermont
Umv of Vermont, Burlington
Vn~ima
Mary Washmgton College, Fredncksburg Umv of Vrrgrma, Charlottesvdle
0
Wm~hmgton
Central Washington State College, Ellesburg East W~hmgton State College, Cheney Umv of Washington, Seattle
O O
IMPACTS OF REMOTE SENSING STATE
N m ~ OF UmanmasirY
51 1950-1951
1900-1961
1971-1972
1975-1976
0
0 A
0 A
o o o
[]
Western Washington State College,
BeUmgham Wtsconsm
Wyommg
Beirut College, Beirut Cardinal Stntch College, Mdwaukee Umv of Wtsconsm Green Bay Umv of W~consm La Crosse Umv of Wtsconsm Madison Umv of Wmconsm Mdwaukee Umv of Wtsconsm Oshkosh Umv of Wmeonsm PLattevdle Umv of Wtsconsm Stevens Pomt Umv of Wh~onsm Whtewater
[]
0
Umv of Wyomm~ Laranue
a Undergraduate Graduate O A
[]
• •
•
Axr-photo mterpretalaon Remote sensmg Atr-photo mterpretatmn and remote sensmg
began to be placed on the analysis and significance of the data rather than on techmque. This is documented by bibhographles compded shortly after the end of this period (Honea and Prentace, 1966; 1968, 1970). Early applications were related to upgrading the lnforrnatlon base and improving the understan&ng of specific urban problems, such as the distributions of neighborhoods with differing levels of economic status, traffic chrectlon and volume, industnal plant location and classification, mapping of land use zones, developmental planning, and the extension of census data using aerial photos (Green, 1956, 1957, Green and Morner, 1959) Important progress was also made m upgrachng information extractaon potentaal of aenal photography m the study of landforms and rural cultural features (Powers and Kohn, 1959). Agricultural apphcataons were significantly advanced through the use of mr photos for the identification of crops in various growth stages as an element of land-use analysis (Burnschweder, 1957, Goodman, 1959,
Karan, 1960). On the physical side, the mterpretataon of natural vegetataon was also examined m detail (Finley, 1960) It is important to note that many uses of aerial photography were buried in the content of the geograpbacal work dunng this tLrne. Only occasionally did footnotes disclose the dependence of research on aerial photography as a primary data source.
1962-Present
A great deal of activity has occurred within geography dunng tlns tame period. In order to facilitate discussion, the actavltaes of geographers during this tame frame are broken down into a number of categories. These include academia, symposia, iournal artacles, texts and reference works, research funchngs, and, professional society, private industry and federal, state, and local government actawtaes Academia In the early 1960s, the expansion of course offenngs m geography accelerated coincident with the mtroductlon of the term "remote sensing" and an
52
j E ESTES, J R JENSEN AND D S SlMONETr
increased interest within the federal government in aerial reconnaissance as a means of obtaining environmental reformation By 1971-72 (based on reformation from S c h w e n d e m a n , Sr. a n d Schwendeman, Jr. 1972, and Eltel, 1972, and response to questionnatres dastrlbu t e d to G e o g r a p h y departments throughout the nation), Estes and Thaman (1974) found that 99 restitutions m 37 states and the District of Columbia offered courses m either remote sensing or aerial photographic interpretation (Fig. 3, Table 1) The pattern expressed by the 1971-72 dlstrlbutaon is one of intrastate expansion and fllhng in between the three nodal areas seen in the 1960-61 chstnbutaon (Fig. 2) Of the 99 mstltutaons m 37 states, some 74 restitutions in 35 states offered graduate programs in geography (Table 1). Thus, in
httle more than a decade, there was an increase of almost 300% m mstltutaons offenng courses and a gain of slightly over 100% m the n u m b e r of states where these courses were offered. Furthermore, there was also a 300% gain in offenngs at schools with undergraduate programs, along with a 120% gain in states with graduate programs (Table 1). In 1975-76, the total n u m b e r of departments offenng courses in remote sensing a n d / o r air-photo interpretation was 165 (Table 1) These 165 departments are m 44 of the 50 states (Fig. 4) (Schwendeman, Sr and Schwendeman, Jr., 1976). The only states where, to the best of our knowledge, departments of geography do not currently offer either remote sensing or photo interpretation are Alaska, Arkansas, Maine, Missouri, Rhode Island, and West Virginia. Thus,
Institutions Offering Geography Courses in Airphoto Interpretation / Remote Sensing 1971-72
,
_
,
f
,
,Y;_!-,,
Y ,(Y
O
'
i
II
•
i
I
'3
~
i
I •
,
.......
i
~ •
'l
' "%
k
~ll • }
)
~o
~
r,l
O~ i
r---
R
/" -~
--
-~
r
+,__ 0
m ] note
Undergraduate
•
Alrphoto
•
Remote Sensing
Interpretation
•
Airphoto Interpretation and Remote Sensing
"
N o c o u r s e s offered and Graduate
refer to d e p a r t m e n t a l
status only
FIGURE 3
EAG/73 rev CED/77
IMPACTS OF REMOTE SENSING
53
since 1971-72 there has been continued expansion in the number of lnstatutmns offenng remote sensmg/atr-photo interpretation (a 40% increase over the 1971-72 figures) A recent article by Nealey (1977), based on responses to questmnnalres marled to restitutions across the country, hsts a total of 103 courses taught in geography departments in remote sensing and related topics. This total represents 22% of a nationwide total of 470 courses in all &sclphnes ldentffaed in his study Even if we accept the mconsistency between Nealey's and our data to be equal for all dlsclphnes (Nealey's 103 courses to our 165), geography's role in remote sensing Instruction is still sigmficant. Geography teaches more mrphoto interpretation and remote sensing courses than any other disctpline m the COU l't t r y
To provide this work with a flavor of current research being conducted by geographers in umversitaes and colleges across the Umted States today, the authors sent letters requesting mdwlduals to provade mformataon concermng their research. From responses received, ~t appears that along wath the mcrease in numbers of courses taught, as noted above, geographers wathm academia have continued to pursue research into the applicataons of remotely sensed data in a vanety of analytical and methodologacal studies Basically expanding on the trend begun in the mld-1950's, geographers have placed heavy emphasis on the analysis and significance of the data, yet in this period with the rapid expansmn of the avatlablhty of data from a variety of systems (actave and passive microwave, thermal infrared, etc.) and platforms
Institutions Offering Geography Courses m A~rphoto Interpretation/ Alaska
Undergraduateo
[3
Graa~uate •
[~
•
Remote Sensing Atrphoto Interpretation and Remote Sensing No courses offered
note Undergraduate and G~aduate refer to departmental status only
FIGURE 4
CED/rr
] E ESTES, i R JENSEN AND D S SIMONETT
54
(both low- and high-altitude and spacecraft), articles wath emphasis on techmques and methodology have begun to reappear Of the responses received, those which are not included m the following section deahng with a more recent trend m geographic remote sensing (1972-present) include. .
Methodological works by: Hsu (1975) on automated pattern recognition of thermal infrared data. The use of a specmhzed (Mahalanobls) classffaer m automated image processmg (Hsu, 1978), and population estamataon from Landsat data (Hsu, 1973) Eyton and others m interpretation and data processing (Eyton, 1978). A process for enhancing the interpretability of Landsat data (Eyton and Kuether, 1978). Klemas and others on the vanablhty of wetlands reflectance and ~ts effect on automatic classification of images from Landsat (Bartlett and Klemas, 1977) An approach to studying estuanne clrctdataon and shelf waste dispersion using satelhte-mrcraft-drogue data (Klemas et al. 1974). Kraus and others on the comparatave detection of marine surface targets as interpreted from real and synthetic aperture radar data (Kraus, et al., 1977). McDonnel and Lewis (1978) on the detection of ship targets on Landsat imagery. Estes and others on the measurement of sod moisture conchtlons wath an airborne imaging passwe microwave radiometer (Estes et al., 1977). Welch (1977) and Welch and Lo's (1977) works on speclflcataon and analysis of image quality and height measurement from satellite data
Tmney and others on the mapping of archaelogical sites from historical vertical and obhque photographs (Tmney et al., 1977). Thomas, Lewis and others on the assessment of snow pack from Landsat data (Thomas et al., 1978), and by Lewis (1977) on coastal mapping wath radar systems 2. Work on land-use/land-cover analysis by Klemas and others on classification of coastal zone land-use patterns from satelhte data (Klemas et al, 1975). Peterson and others on an inventory of the wetlands of the state of Nebraska using Landsat satellite data (Seevers et al., 1975). Rehder on changes which occur m the landscape as a result of strip mlnmg (Rehder, 1976), and momtorlng landscape change from Landsat data (Rehder, 1973) Mower and others on the development of a computer processed land-cover map of the state of North Dakota (Mower and Helnrlch, 1977); and on the dlscrtmmatlon of land and water resources using multtspectral remote sensing techmques (Mower, 1976). Walsh (1978) on dafferentlatlon and mapping of coniferous tree species. Henderson (1977) on the use of radar imagery m the analysis of Land-use patterns. 3 Works on areas outside the United States by. Comer (1977), on apphcatlons of remote sensing to the development of urban information systems m In&a. Klemas on the apphcatlon of satelhte data to the management of food resources m developing countries (Klemas and Leu, 1977). PanneU and Welch (1976) on recent satelhte coverage of Cbana. (Welch and Pannell, (1975) on investigation
IMPACTS OF REMOTE SENSING
of recent urban land-use change in Northeast China, and (Lo, et al., 1977) on land-use changes and city planmng m Shenyang and Canton, China. In addition to these pubhshed works, researchers under Ray Lougeay are workmg on the use of Landsat data for the mapping of buried glacier ice. Norbert Psuty and researchers at Rutgers Umverslty are working on the analysis and delineation of submerged coastal vegetation. Ramer Erhart at Western Michigan University is working with Raymond Price on the ongan of hnears in a glacial environment in Southwestern Mlchtgan. Gary Hlggs of Mississippi State Umverslty is mvestagatmg the applications of remote sensing to a variety of land-use/ land-cover topics lncluchng beach erosion and cotton mapping. Symposia A factor which has contnbuted to the growth of interest m remote sensing in the United States is the increasing number of remote sensmg symposia, the first and still most prestaglous symposia being the senes conducted by the Envaronmental Research Institute of Michigan (ERIM) at the Umverslty of Michigan and other sites. This symposmm senes resulted initially from recommendations of a subcommittee of the National Academy of Sciences--National Research Council and the Geography Branch of the Office of Naval Research (Institute of Science and Technology, 1963). The subcommittee met in January 1961 to discuss the need for more advanced and efficient data acqmsltaon techmques m the earth sciences. The symposia were imtaated to provide a periodic forum for assessmg developments m the field of remote sensing
55
The First Symposmm was held in February 1962. There were 72 partlclpants including five geographers. At the Seventh Symposmm, held m May 1971, there were 850 partaclpants, lncludmg 46 geographers (Fig 5) At the Tenth Symposmm (1975) there were 16 geographers out of 645 attendees, whde at the Eleventh Symposmm held m April, 1977, there were only 8 U S geographers out of 497 registered attendees. One paper (of 15) was presented by a United States geographer m 1962, 12 (of 173) m 1971, 12 (of 132) m 1973, 9 (of 155) m 1974, 5 (of 146) m 1975, 9 (of 172) m 1977, and 11 (of 226) m 1978. Respectively, these percentages are 7, 7, 9, 6, 3, 5, and 5. Whether the absolute decline in attendance at these symposia and m the relative number of papers presented by geographers in recent years is real and reflect a disinterest among geographers m research in remote sensing, or whether it is an artifact, we do not know. There are now other remote sensing symposia which draw geographers away, and the Michigan Symposia are also held each year at a time near to or coincident w~th the annual meeting of the Assocmtion of American geographers (which in adchtaon now schedules 3 to 5 sessions on remote sensing). lournal Articles Few artacles deahng with remote sensing related topics have appeared in major Umted States professional geographic journals The authors are not sure how to interpret tins. It may arise partly because of the traditional nature of the arttcles accepted by these journals. Have the edators consciously refused technical articles on remote sensing believing that they are too technlqueonented for their journals? Tins may mdeed be a factor. [In the late 1960s, it
st
2nd 3rd
4th 5 th
6th
7~h
Itttttl
_I 10 th
11 th
YX)
5OO
Remote
FIGURE 5
Sensing
~ymposla
Bth
0
I00
9th
~+ ÷+ +~
~0 I
~+++~
~-~-++t
_>00
I
ii;i~;:;
L0
~0
~0
)0
6OO
~oo
?0
!!!!!!] 700
j
m
10
~0 I
}0 i
~,ttendance And Papers Presented By U S Geographers At Remote Sensing Of Enwronment Symposia Held At The Untverstty Of M~chtgan 1962- 1977
@ Z
t~ Z
F1
IMPACTS OF REMOTE SENSING
certainly motivated the geographer Edward Rlsley, then a staff member of the National Academy of Sciences, to push for an mterdlsclphnary refereed outlet for remote sensing articles At the hme neither geographic nor other professional journals were very sympathetic to remote sensing articles. Rlsley's discussions with Amencan Elsevier (now Elsewer North Holland) led to the establishment of Remote Sensing Of Enwron-
ment
An
Interdisc~phnary 1ournal ]
Whatever the reasons, geographers generally publish on remote sensing topics outside the chsclpllne. For example, between 1960 and 1976 only seven articles dealing with air-photo lnterpretataon/remote sensing appeared m the Annals of the Association of American Geographers, and three in the Geographical Rewew, whereas 12 articles by geographers appeared in Remote Sensing of Environment and 42 in Photogrammet-
r~c Engineering and Remote Sensing Remote Sensing of Enwronment, which was started w~th Dawd Slmonett as edator and is presently edited by Freeman F. Hall of the Natmnal Oceanic and Atmosphenc Admlmstrahon (NOAA), has served as an outlet for geographers. Pho-
togrammetr~c Engineering and Remote Sensing, the journal of the Amencan Society of Photogrammetry, is one of the most slgmficant single outlet for remote sensing articles written by geographers, and others Texts and Reference Works. It is interesting to note that one important way which geographers have Impacted remote sensing is through pubhcatlon of texts and reference works. The works of Holz (1973) Estes and Senger (1974) Rudd (1974) Lmtz and Simonett (1976) l~chason (1978) and the just published volume e&ted by personnel of the
57
Center for Urban Pohcy Research (Ford, 1979), are evadence of the commitment on the part of geographers to upgra&ng the quahty of information and instruction m remote sensing. The Manual of Remote Sensing published in 1975 provided additional evidence of this (Reeves, 1975), as 2 of the 8 volume editors, 7 of the 51 chapter editors and 35 of the 236 contnbutors to the Manual of Remote Sensing were geographers. On the face of it, these figures appear encouraging On closer scrutiny, however, we are not sure this constatutes research commitment on the part of the geographers, or a lack of it in significant areas by professionals in other disciplines, or to the operahon of an old-boy network among geographers! Research Funding Teaching and pubhcatlon in remote sensing by geographers may be, but are not necessarily associated with advanced research Research on remote sensing topics can be a very expensive undertakang. It is not surprising, therefore, that almost all of the major academic research m geography dealing with remote sensing is funded by agencies of the Federal government. It has essentially been thts federal support which has influenced and created the envaronment for growth in the field of air-photo interpretation/remote sensmg In all &sclphnes At the present time federal funds come mainly from the National Aeronautacs and Space Administration (NASA), either directly from NASA Headquarters or through other federal sources. In addition, various NASA research centers (e.g., Goddard Space Fhght Center, MD, Johnson Spacecraft Center, Houston, TX, and Ames Research Center, Moffett Field, CA) also provide research funds either dtrectly or through various user agencies or groups Other agencies of the
58
Federal government who presently fund geographic research in remote sensing or have provided funds in the past include the Geographic Apphcatlons Program (GAP), of the United States Geological Survey, Earth Resources Observation Systems (EROS) Program, United States Department of the Interior, Office of Naval Research Geography Program, Advanced Research ProJects, Army Engineering Topographic Laboratories, United States Department of Agriculture, the Department of Housing and Urban Development, Department of Transportation through the United States Coast Guard, and the National Oceanographic and Atmospheric Administration, Department of Commerce. Professional Soczety Activities In May 1967, the Association of American Geographers showed interest in remote sensing as a research tool in geography by forming a Commission on the Geographic Apphcataons of Remote Sensing under the direction of James Anderson with Robert Pephes as Executive I)arector An AAG Committee on Remote Sensing was also formed The commission has since ceased to function while the Committee continued to promote educational programs in remote sensing within the dlsclphne through institutes, short summer courses, and workshops. Five short summer courses were sponsored by the National Science Foundation and the Remote Sensing Committee of the AAG to acquaint college level teachers with new remote sensing technology In addition, the Remote Sensing Committee has sponsored remote sensing workshops in connection with AAG's and National Councd for Geographic Education (NCGE) national meetings. More recently the NCGE has also formed a
j E ESTES, J R JENSEN AND D S SIMONETI" g r o u p , This g r o u p in cooperataon w i t h
members of the AAG's remote sensmg committee have been responsible for the workshop at their National meetings The NCGE is also sponsoring the pubhcatlon of a text and workbook on remote sensing (Rlchason, 1978). Attendance at both AAG and NCGE workshops has been excellent and may well be a major factor in stimulating the growth of teaching in remote sensing in geography. Another significant activity of the Remote Sensing Committee of the AAG has been the pubhcation of the newsletter Remote Sensing Quarterly, formally called RSEMS--Remote Sensing of the Electromagnetic Spectrum. Pubhcatlon of RSEMS began in 1974 as a quarterly with a subscription fee of $1 00 per year. The first issues could be characterized by the whimsical motto internally proposed for adoption as the RSEMS logo "Quidman Sesterao Nummo exspectasses" (essentially, "What on earth did you expect for 25e"). As RSEMS has continued, it evolved into a useful, though pnnclpally pedagogac, rather than research quarterly with over 1000 subscribers The editorial staff and guest echtors have concentrated on specific topics (e.g. radar, classroom materials, and laboratory exercises). RSEMS filled a need within geography as an outlet for the smaller research results and as a forum for the exchange of news and ideas. Its improvement over the past four years to a great extent parallels the increasing awareness of geographers to the potential of this tool. With a new editorial staff and active sohcitataon of more substantial research artacles, there is hope that the retltled Remote Sensing Quarterly wall eventually achieve a level of quahty and status equivalent to Geographical Analys~s. The latter is a pub-
IMPACTS OF REMOTE SENSING
hcation which began out of the frustration of quantitative geographers in even finding a voice for thetr research in the traditaonal, essentially antamathematacal antatechmcal geographic U.S. journals in the late 1960's. [This was the same tame as when Remote Sensing of Environment was being established, and for much the same reasons!] Over recent years national meetings of the AAG have increased the number of sessions on remote sensmg, thus drawing geographers away from the nearly coincident Michigan Symposium. There were four sessions on remote sensmg at the AAG National Meetangs in Salt Lake City (1977), five m New Orleans (1978), and several more in Phdadelphia (1979) We confidently expect this level of evident interest and need for appropriate outlets within the &sclphne to contanue to increase Prwate Industry, and Federal, State and Local Government A ctiv~tws Within the period 1962-1977, two rapidly advancing areas of research a n d / o r employment of m&viduals with a background in geographic remote sensing should be mentaoned. These are (1) private mdustry, and (2) state and local governments. The 1967 directory of the Assocmtaon of American Geographers listed 7 geographers in government jobs and 3 m private industry wath a specialty m remote sensing. By 1974, the year of the latest AAG directory, the number of geographers listing a remote sensing specialty had climbed to 43 for government and 36 for private industry. There is every reason to believe that tins rate of ,ncrease is aceeleratang, A complete listing of the industries and goverumel~t agencies where professional geographers with remote sensing interests are em-
59
ployed is beyond the scope of this paper. However, these include such companies as Lockheed Electromcs, Rockwell Internataonal, General Electnc; Earth Satelhte Corporataon, Electromagnetic Systems Laboratory, Spectral Data Corporatlon, Dames and Moore, Henmngson, Durham and Richardson, Tetratech, and others. Within state governments, geographers with remote sensing backgrounds are employed in planmng, environmental protection, and resource development agencies. For example, in Kentucky, then Governor Carrol designated a geographer, Bill Franklin, to serve as his representatave on an Important committee on remote sensing of the National Governors Assocmtion. Federal government geographers wath remote sensing interests are employed in the Bureau of the Census, NASA, Environmental Protection Agency, Geological Survey and Department of the Interlor's EROS Program The Geography Program of the United States Geological Survey is concentratang ItS efforts on land-use analysis and the development of standardized compatible (compatible wath exastlng classificataon systems and with identafiable features as seen on remote sensmg imagery) methods of describing land-use on their new nataonwide 1:100,000 land-use senes. In support of tins nataonwade land-use mapping effort, personnel of (or working for) the Geography Program have pubhshed a wide variety of remote sensing articles including works by' Anderson et al., (1976) on the development of a landuse/land-cover classificalaon system for use with remote sensor data, Anderson (1977) on land-use and land-cover changes and the estabhshment of a
60
j E ESTES, J B IENSEN AND D S SIMONETr
gmmng in the early 1970s, is on the combination of data from different sensors and different times to improve the modehng of complex environmental phenomena. Improvement in both type and quality of input data may potentially be aclueved m many models through the use of spatially-distributed remotely sensed data rather than lumped parameter data. Conventional methods of presenting reformation of vanous areal umts usually assume a homogeneous dastnbution of parameters throughout a data collection unit at a gwen scale. Remotely sensed data, however, offer the p o t e n t i a l to either correctly map or to &saggregate these data and redistribute them m a way which more closely approximates the "real world" chstnbution In adchtlon, due to the time sequential (multitemporal) dimension of data from systems such as the Sun Synchronous Meteorological Satelhte Geostationary Orbiting Environmental Satelhte (SMS/GOES) and Landsat, the time frames over which data can be supphed as drivers for model operation IS also being improved. With the satellites hsted above, data collection for the same geographic locations range from every 30 mln to every 18 days, and although the scales from these satelhte systems vary considerably, the systems presenting higher resolution data may be employed to cahbrate and verify the lower resolution data. Although this type of analysis wdl be chscussed m more detaal later (under the 1972-Present section on functional and ecological sysAlthough the period just chscussed ex- tems analysis), a few comments are aptends through the present, the authors propriate here Dunng the last three or believe a slgn~cant new phase in geo- four years work by geographers which graphic research with remote sensing incorporates remotely sensed data into data has begun. This new emphasis, be- modeling of environmental phenomena framework for monitonng such changes, Alexander et al., (1976) on the apphcations of Skylab data to land-use and chmatologtcal analysis; Ackerman and Alexander (1975) on designing a national land-use information system, Ellefsen et al, (1973) on machine processing of early Landsat data for the derivation of urban land-use reformation; EUefsen et al., (1976) on computer-aided mapping of land-use, Feng et al., (1973) on the development of an operational apphcation of orthophoto mapping techmques for use in a system designed for the detection of change m urban areas, this was preceded by Jim Wray's (1972) work on the cartographic aspects of an operational system for detecting urban change by remote sensing, Dolan and Vincent (1973) on coastal processes, and, Tomhnson et al (1976) on computer handhng of geographic data The October 1977 issue of RSEMS (Vol. 4, Number 4) discusses the work of the Geography Program Other articles by the Program include those by Fltzpatnck-Lms (1978) on accuracy and consistency comparisons of land-use/ land-cover maps complied from high-altitude photographs and Landsat muhlspectral tmagery, Guptill (1978) on optimal filters for maps showing nominal data, and Mitchell et al., (1977) on GIRAS a geographic information retneval and analysis system for handhng landuse and land-cover data
IMPACTS OF REMOTE SENSING
have dealt mmnly wath agricultural and land-use related topics: Land-use/land-cover (Harwood et al, 1977, Wllhams, 1977) 2. Estimates of winter wheat yields (Morton and Wllhams, 1973, 1975). 3 Momtonng of spring wheat production (Slmonett et al., 1974). 4. Agricultural water demand modehng (Tmney et al., 1974, Estes et al., 1975, Jensen et al, 1977; Estes et al., 1978). 5. General crop inventory (Jensen et al., 1975; 1978).
61
2.
1.
3.
4.
1980, Nicholas and Lewis, 1980). Populahon census actwltaes (Chnstenson and Lachowslo, 1977; and General Electric Co., 1977). Slte/specws vegetahon modehng (Strahler et al., 1978, and Woodcock et al., m press). Snowmelt distributed parameter modehng (Dozier, 1979)
A Perspective on the Present Status of Remote Sensing in Geography
As can be seen from the preceding discussion, remote sensing m geography Other areas where geographers are beginnmg to apply remotely sensed data in has made rapid strides. This development a modeling context have begun to ap- has, however, been coupled with some major disappointments. The number of pear These include lnstitutaons offenng courses in remote 1 Hydrologac modehng (Sohn et al., sensing have increased significantly. 1976, Sasso et al., 1977, Baker et al, However, pubhcahon m major reviewed 1975, Holz et al., 1977). journals within geography has lagged and 2. Modeling of phenomena m the urban the share of substantive research camed environment out by geographers in the overall area of (A). Water demand (Jensen et al, remote sensing may even have declmed. 1977). It is perhaps unfair, but may be close to (B). Land-use change and effects (B1the truth, to say that geography today llmgsley and Bryant, 1975; Estes appears to be moving toward a teachmgand Jensen, 1975; Bryant, 1976, only disciphne with respect to remote Bryant and Zobnst, 1977; sensing, relahvely unaffected by major Bowden, 1979, Pease et al., research programs. On the other hand, 1976, 1977). we could suggest that tlus is a transition (C). Distributed parameter energy phase and that as the teaching programs demand modeling (Clayton and take hold, backgrounds tmprove, and Estes, 1979). graduate students become more and (D). Urban chmatology (Pease and more involved sohd geographic research Nichols, 1976, Lewis, 1977, in remote sensing will expand. It can also Lewis et al., 1976). be argued that other disciphnes, proportionately, seem to be influenced less We are also aware of additional stu&es by remote sensing than geography as now underway, or in press, including: shown by the lesser teaching impact We 1. Land-use chmatology (Pease et al., are, however, suspicious of arguments
62
either way, as such arguments are often based on inadequate and potentially biased and misleading surveys Simply stated, at this time, we are not sure whether there is a firm basis for either hand wrlngang or self-congratulations for any disclphne What is the true measure of the impact of a new technology upon a dlsclphne 9 Is it the prohferatlon of new courses~ The amount of research funds acqmred? The number of publications m scholarly journals9 The acceptance of the technology by recognized leaders m the &sclphne or perhaps even more signffacantly outside the dlsclphne9 As seen above, we are unsure of what answers in these areas m e a n We are sure that there has been a significant increase in the number of remote sensing courses taught in geography and that there is a considerable but unrealized potentml for research funding There have been few refereed remote sensing publications within the major geographic journals, whde geographers contanue to contribute to specialized remote sensmg journals. Finally, there appears to be a lack of acceptance and use of the technology by recognized leaders m the field though this is somewhat counterbalanced by the slgmficant number of departments seeking competent jumor faculty in remote sensing as shown by recent professional advertasements Through this mire of confllctang evidence, what measure should we seek Is ~t possible that the true measure of remote sensmgs's impact on geography is dependent upon how well it allows the geographer to more effectively test hypotheses9 What types of hypotheses do geographers work from9 What are the current modes through which geogra-
j E ESTES, J R IENSEN AND D S SIMONETI"
phers analyze chsclpllnary questions? What analysis techmques are best suited to production of data relevant to such hnes of investigations? In addition, do geographers have a perception of remote sensing as a research area where hardware, software purchase, a n d / o r development time is not worth the physical and/or psychological costs of retoohng9 In all of this we should keep in mind that many semor geographers already have a body of data sources and analysis techtuques with which they are comfortable. These sources have served them well and their professional reputations may even be based on their skdl in employang them Why should they change and employ remote sensing data9 If we can begin to answer this question we approach the heart of the problem, truly defimng the real and potential Impacts of remote sensing on the dlsclphne. In an attempt to do so let us first exarmne some basic foundataons of the dlsclphne and then consider the theorettcal and practical role of remote sensing m geography
The Theoretical and Practical Role of Remote Sensing in Geography Geography traces its ongans back to the ancient Greeks. It is said that Herodotus (484-425 B.C.) IS not only the father of history, but of geography as well (Brock, 1965). Herodotus achieved this dastmctlon because he placed tustoncal events wltlun a geographic setting by gavang descnptave topographies of the places where events occurred. Bernhardus Varemus (1622-1650) was among the first to present the structure of geography as a sclenttfic dlsclphne. Varemus proposed a dwlsion between what he termed general and special geography.
IMPACTS OF REMOTE SENSING
General geography deals with physical phenomena for which umversal laws could be formulated whale special geography examines particular areas of regaons of the earth as they derive their character from the interaction of human and physical processes. Although Varenlus presented the structure of geography as a chsclpllne, it was Immanual Kant (1724-1804) who secured its foundations within the framework of the phdosophy of science According to Kant, all knowledge is separable into three categories. (1) one which sorts facts into groups accorchng to the kinds of objects or phenomena studied, e.g., the systematic sciences of botany, geology, etc., (2) another which sorts facts to vaew them m their relationships through time, e.g. the historical sciences, and (3) the study of things as they are assocmted m space, Le. the prownce of geographical science. This Kantmn wew that spatial analysis is the center piece of geographic thinking is frequently presented as the fundamental justification for geography. It is, m fact, one of the major foundations of Rachard Hartshorne's treatise on the Nature of Geography (1939). A number of geographers, on the other hand, regard the Kantian wew as too snnphstie, arguing that each of the chwslons of knowledge can be viewed from each of Kant's three vantage points and that geography, rather than being a basic diwslon of knowledge, is more a method of wewmg and characterizing environmental relationships. David Harvey, m his book Explanation in Geography, suggests that the following six explanatory forms are employed m the discipline:
1. Cognttive descriptions. This may range from srmple, prmaary observa-
63
tions to sophisticated, statements.
2
3
4
descriptive
Morphometrtc analys~s. In some ways, tlus may be regarded as a type of cogmtive description, one revolving a space-time measurement relationslup rather than a property language. Cause-and-effect analysts This is the insistence that cause-and-effect be established m order to explmn the occurrence of environmental distributions. Temporal modes of explanation From causal explanation, it is a short step to causal chmn explanation which stretch back over tame.
5. Functwnal and ecologwal analysts, This is explonng phenomena m terms of the role they play wltiun a partacular social or enwronmental orgamzation. 6. Systems analysis. Tins is the basis for describing whole complexes and structures of activaties. It ~s only a short step from analyzing the function of a partacular phenomena within an orgamzational framework to studyang the structure of that orgamzation as a system of interlockmg parts and processes. One might reasonably ask what Is umque about these? Surely other natural and social scientists employ the same explanatory forms. The authors are aware that there may be debate concerning these forms; nevertheless we accept them here as a statable basis for structunng the remmnmg discussion However, as we perceive a substantial overlap m the SLX explanatory forms, we have taken the liberty to combine them as follows (1) morphometnc analysis, (2) cause and
j E ESTES, J B JENSEN AND D S SIMONETI"
64
effect analysis, (3) temporal analysis, and (4) functional and ecological systems analysis Within each of these aggregated explanatory forms we pose these questaons 1
2
3.
what does remote sensing permit the geographer to do now b e t t e r than he or she has been able to do in the past9 what does remote sensing permit the geographer to do now that he or she w a s u n a b l e to do m the past, and finally~ what may remote sensing enable us to do in the future winch could be of significance to professional and academic geography9 Morphometric Analysts
Geographical research usually requtres measurement to determine the structure and m o r p h o l o g y of p h e n o m e n a Measured attributes of phenomena may be generally classified as being (1) physical properties, (2) spatial (geographical) properties, or (3) temporal properties. In any type of analysts it ts important to obtain quantitative mformataon concernmg these parameters m addition to descnptave evaluation. Remote sensing plays an important role m prowdlng mformataon on the physical properties of phenomena. In particular, an object's energy response sensed in wavelengths or frequencies throughout the electromagnetac spectrum may prowde quant~tatave data on such properties as geometry (size, shape, arrangement, etc ) spectral color or wsual appearance, temperature, chelectnc nature, mols~re content, and organic and inorganic composition. I n s , t u (or trans-
ducer) investigations are typically costly and are site specific, provachng only pomt observation that must be mterpolated to yaeld a geograpincal surface Remote sensing, on the other hand, may provide both point (per picture element) and areal physical property reformation Tins bnngs us to the next topic of discussion, the measurement of spataal (geographical) properties Geographical data may range from simple zn s i t u observation where the spatlal properties are not important, to complex analyses where the properties of phenomena are most significant when viewed m relatson to their spatial association with other phenomena As geographers are pnmanly concerned with the latter type of morphometnc analysis, it is not surprising that the profession contmues to be interested m hard-copy remote sensing imagery or quantlzed digital data m a matrix format which can be reconstructed to yaeld an image for either interpretation or photogrammetnc analysis if desired Such two-dimensional, and with the proper parallax, three-dimensional (stereoscopic) data provides the geographer with a synoptic view of local or regaonal environments often unattainable from m s , t u data collection. To avoid the connotation that remote sensmg ts always supenor to m s , t u m vestlgatlons, consider the blogeographer who, with aenal photography of hts study area unavadable, discovers that the spatlal resolution of Landsat data ts not capable of provl&ng specific information. Nevertheless, the Landsat imagery, although Impractical for the specific task at hand, might still prowde valuable collateral or surrogate reformation that could significantly affect subsequent m-
IMPACTS OF REMOTE SENSING
65
formataon, winch m turn could signifi- obvaous spataal errors m preremote senscantly affect subsequent lnvestagataons. ing maps where rivers, mountain ranges, T h s points out a fundamental character- and even the spatial dimensions of contilstac of remote sensing when apphed to nents were m error. Thus, remote sensing morphometrlc analysis problems. At a wall allow the geographer's large-scale gaven scale it may prowde specific types and small-scale basemaps to become of categorical lnformataon by Itself, or It more accurate. This has been significan be used as a method of stratff3nng cantly affected by the Landsat satelhtes (Le., regaonallzlng) an area for subsequent winch have a semiangle of only 5.76 ° off analysis Using multiple scale images, it is nadir yielding essentially orthographic posmble to stratify regions and design maages. Landsat's plammetnc spatml samphng strategaes wbJch among other fidehty is such that (once it is system-corthmgs may (a) reduce the time and costs rected to ehmmate periodic system assocmted wath samphng, (b) maprove the errors) it meets national map accuracy power of a samphng design through prior standards at a scale of 1.500,000 and m ldent~catlon of appropriate areas (strati- several respects meets 1 250,000 stanfication), (c) reduce the number of sam- dards as well. pies needed to acineve a specified preciCoupled with tins increased capabdlty sion, and (d) slmphfy lnterpretataon. to accurately locate basemap data is the With the understan&ng that classify- very maportant contribution of remote mg phenomena a n d / o r stratafymg homo- sensmg to thematic cartography The geneous regions is an important role for "themes" of data (e.g land use) capable remote sensmg, let us continue to of being extracted from analysis of a evaluate the impact of tins technology's gaven image may be apphed to the previsynoptic, spatially accurate view on geo- ously discussed accurate basemap to imgraphic morphometrlc research. This can prove both the spatial and categorical best be understood by considering the accuracy of the geographer's thematic map, winch is geography's pnnclpal map me(hum for commumcatlng spataal reforAs a result of tins threct impact on mation. Prior to the development of re- basic and thematac map theory, cartogramote sensing, scientific maps were com- phers more than most anticipate the role pded from terrestrial observations. Such remote sensmg may eventually play in maps were only as accurate as the geographic research and education. Tins terrestrial field-of-wew, Instruments, and is because cartographers are reqmred out experience of personnel complhng them. of necessity to understand and utlhze Contrast ths with the present situation remote sensing technology. Consewhere the geographer's basemap, Ins quently, it is not surprising that 38% of maanstay of accurate 2-damenslonal com- the 60 geographers teacinng remote sensmumcation, is for all practical purposes ing m the Umted States m 1976 hsted almost totally derived from a combma- cartography as one of their speclaltaes taon of photogrammetnc and photolnter- (AAG, 1976). Interestingly, in 1977, we pretataon techmques. Koeman (1970) and find cartographers proposing the techmColvocoresses (1975) have pomted out cal parameters for an operational Land-
66
j E ESTES, J R JENSEN AND D S SIMONETI"
sat. In their words, consider the impact of satelhte imagery on spatial (geographical) problems It may seem presumptuous for a cartographer, or group of cartographers, to undertake the task, but the cartographers who would map tius Earth have as great a stake m Landsat as any other dlsclphnary group Geologtsts, agriculturists, foresters, and land use planners, as examples, are equally revolved, but thetr operatmnal use of Landsat depends m no small part on the solutaon of eartograpluc problems These m turn depend on relatave and absolute geometry as well as the mformalaon content of Landsat data There ts probably no other concerned group as demanding as cartographers and, from what we have seen to date, Landsat data when properly processed can meet its demands for the plammetne portrayal of the coarser Earth-surface features (Colvocoresses, 1977)
Stall other evadence of the united wewpolnt of remote sensing specmlists and cartographers is given by the numerous artacles on "image processing" appearing m cartographic journals (Muehrckl, 1972, Monmomer, 1976) and data handling symposia throughout the 1970's (Tomlinson, 1972). In effect, cartographers and remote sensmg specialists understand that whether one deals wath a map or a photograph xs immaterial. The fundamental goal is to produce and communicate the reformation contained in each so a meaningful concluslon can be drawn. Thus, we find both cartographers and remote sensing speciallStS concerned with essentially the same topics First, how to collect information either in the field or with a sensor system; and second, how to interpret and unambiguously communicate the results be it m a map or image format. With so much in common it is understandable that numerous essentially cartographic problems have been addressed and
answered within the realm of remote sensmg research dunng the last decade. Cause-and-Effect Analysis Obwously, the synoptic view just discussed has important lmphcat~ons for regional studies whtch attempt to identify cause-and-effect relationships between phenomena visible on the landscape. The German geographer Alfred Hettner expressed the view in 1898 that "mere description has been replaced m all branches of geography by search for cause" (Hettner, 1898). The estabhshment of cause-and-effect relat~onslups is central to researchers m all branches of scientific endeavor. By employing sensor systems sensitive to electromagnetic energy both within and outside the visible spectrum, it is possible to enhance our capabdlty to determine causation, define causal pnncxples, or enuncmte causal determinism by increasing our abdlty to percewe effects which for a variety of reasons may be beyond our direct visual experience. This may include percewmg a given wavelength of energy outside the wslble spectrum and/or assuming a viewing perspective for a sufficient period of time (e.g., geostatlonary satellite) to adequately momtor phenomena. Man has always perceived the end resuits of processes acting on his surrounding (effects) and attempted rational explanations based on his current level of knowledge, experience, and understanding In his work on the nature of geography, Harshorne devotes considerable attention to a discussion refuting the view that there be a hnutation on geography to things perceived by the senses. In h~s discussion, Hartshorne states that geographers "have long recograzed in prac-
IMPACTS OF REMOTE SENSING
tlCe that, for many of the features that all agree must be studied, we cannot depend upon any direct form of observation." Hartshorne summarized his extended chscusslon of the question of the hmltatlon of geography to areal phenomena which are "in general, visible" by stating that such a view would "d~srupt even a central core of 'pure geography' by placing certain aspects of areas outside of the geographer's field of study, except that he later finds it necessary to investigate them in order to interpret what he has studied." What IS implicit in Hartshorne's discussion is that techniques by which we may expand our perceptions of our environment to permit a deeper, richer understanding are well within the analytic preview of geographers Remote sensing offers the important capability to extend our detection and understanding of effects which were until now basically beyond the hmlts of our perception and effective measurement. For example, a thermal infrared scanner can record temperature differences in a nver to pinpoint the location of a thermal plume undetectable to the unaided human eye Similarly, reflective near-infrared photography has been used to detect biophysical stress (i.e., effect) before the cause (e.g, loss of moisture from pathogens) is detectable in the visible spectrum. In addition, earth synchronous meteorologacal satelhtes in geostationary orbits such as SMS/GOES are just one of any number of satellites providing researchers with synoptic temporal data helpful in the determination of cause and effect relationships which would be unpossible to obtain in any practical sense without the use of remote sensing technology The capability of remote sensing
67
to provide such data demonstrates the expanded potential for the generation of basic source material offered to geographers on topics previously chffieult, if not impossible, through the judicious application of remote sensing technology. In addition to the multispectral attributes present in a gwen cause-and-effect relationship, the ability to perceive the simple geometric shape of phenomena as they progress or regress is tmportant For instance, the geometry of suburban sprawl, insect infestation, flood lnnundatlon, fault related topography, erosion, etc., as they appear on successive synoptic images represent valuable sources of information which may be used to identify cause-and-effect relationships. Without such data the researcher may be seriously handicapped in malong conclusions related to geographic research. This potentaal of remote sensing, however, has stall not been substantively employed by geographers. However, we anticipate that the space systems of the 1980's (Landsat-D, Multispectral Resource Sampler, Magsat, Stereosat, the Space Shuttle, etc.) will offer opportunities for its use. Indeed, because of the lrnproved spectral, spatial, and temporal resolutions expected from the coming space systems, it is incumbent upon geographers to actively use the new data, or isolate themselves from an essential part of the new geography. Other chscIphnes will not allow any inches to remain unoccupied!
Temporal Modes of Explanation Although most geographers would agree that spatial variation IS of prime concern whde history concerns itself with change through time, the geogra-
68
pher cannot ignore the temporal domam nor can the historian chsregard the unphcataons of space. The geographer's concern w~th tame stems from two pnncapal consaderataons. 1. A concern wath the explanataon of observed phenomena, such explanahons typacally mvolve an analysis of processes and sequences whach occur through tame. Typacally explanataons of ttungs observed m the present have roots m the past 2. Change through tame as an maportant charactenstac of place, and vanataons m rates of change of the components of a gaven locataon conshtute an amportant spataal varmble (Hammond and McCullagh, 1974). As Hartshorne states m has chscussaon on "Tmae and Genesas m Geography" m Perspectwe on the Nature of Geography, "To the best of my knowledge, no competent student of the methodology of geography has ever asserted a statac concept or faded to recogmze that the dimensaon of tame as always revolved" (Hartshorne, 1959). "Change" to geographers then, as synonymous with process and sequence. Thus, to be able accurately and consastently to adentafy change m a spataal framework as an amportant part of any morphometnc cause and effect or functaonal and ecologacal systems mvestagataon The capabdity to vaew objects a n d / o r phenomena an their spataal context through tame an a broadly consastent manner as potentaally one of the more amportant contnbutaons of remote sensmg to geography. Inconsastent data sources currently plague temporal stuches. Landsat data, on the other hand, is a reasonably anternally consastent, longatuchnal (i.e., temporal) data set. What are the internally consistent features of Landsat which promote geo-
j E ESTES, J R JENSEN AND D S SlMONETr
graphic (temporal) analysls~ Landsat has been placed m a sun-synchronous orbit so as to trnage the same geographic area once every 18 days (9 days if t w o satelhtes are used) at very nearly the same tame, scale, geometry, look angle, and sensor configuration. Consequently, change of a great dwerslty of phenomena may be assessed rapidly through multadate subtractaon techmques or through rahomg channels of chfferent dates. Here agmn, as satelhte data with tmproved spataal resolutaon generally becomes avadable (e.g, 40-meter Return Beam Vldlcon on Landsat-3 (launched March 1978), 30-meter Thematac Mapper on Landsat-D (to be launched 1981), 15-meter Multaspectral Resource Sampler (to be launched possibly mld-1980's), our abdaty to employ these data to monator the sequence of phenomena whach constatute process wall become even better. In the fnal analysas, the acqtnstaon of single date or multatemporal data depends upon whether the geographer as concerned with statac or dynamac phenomena If he as pnmardy concerned with relatavely statac phenomena (e g, sods, slopes, rock types), single or widely spaced (m a temporal sense) observataons may be sufficient If, on the other hand, he as anterested an dynamac phenomena the temporal resolutaon of the systems chscussed above as Lmprovmg to a pomt that certmn dynamac processes (e.g., runoff, flooding, crop growth, moisture response) may be effectavely modeled w~th an accuracy heretofore unattainable. In addahon, by anterrogatang an mteractaon matrix between statac and dynamac phenomena driven with remote sensmg supphed data, much detailed mformataon concernmg the functaomng of both statac and dynamac elements present
IMPACTS OF REMOTE SENSING
in a given landscape might be achieved. In traditional geographic research, the high-temporal resolution required to drive such models is obtainable only by extensive costly data collection platforms (DCPs) a n d / o r field work As seen in the discussion concermng developments from 1972 to the present, the first remote sensing aided models that attempt to systematically acquire data with a high-temporal resolution are currently being evaluated. With the aid of remote sensing, systematic analysis of multldate change detection for a variety of environmental processes may be possible. By the apphcation of multldate change detection techniques, geographers may be able to quantify the rate and perhaps even the geometry of many processes at work m our environment. Probably the biggest handicap to this type of apphcataon, however, will be the requirement that investigators be famlhar with the imaged data (in either analog or dlgatal formats) to be interfaced with their traditional nonremote sensing data sets (e.g., the census). This topic wdl be addressed m the following section Functional and Ecological Systems Analysis
All the previously discussed roles of remote sensing in geography are involved m systems analysis. It is here that the data must be transformed Into reformation to help make a division or to understand a process While geographers often require spatially accurate data for both mlero- and macroscale phenomena, efficient or accurate methods commonly do not exist for collecting these data. Remote sensing offers some of this needed potential and is beglnmng to be
69
apphed to systems analysis at both ends of the spatial continuum. For instance, the authors, other geographers, and scientists m other ¢hsclphnes with remote sensing backgrounds are exarmnlng the information gained by the apphcatlon of ¢hstnbuted rather than lumped parameter models to a number of physical processes and cultural phenomena (e.g., multacrop inventories, monitoring snowmelt runoff, developing models for momtonng urban expansion, and energy consumption). Although data of varying degrees of completeness are available through conventaonal procedures in these areas, they are used primarily In lumped systems. The use of remote sensing and distributed-parameter models together appears attractive in several ways First, remote sensing data, which is inherently distributed (i.e, spatially dlsaggregated) has proven not easily or inexpensively compatible with exlstang lumped models. The latter are not designed to accommodate remote sensing inputs. Remote sensing data, however, are Intrinsically more compatible with dastrlbuted systems. Second, distributed models, both because of their greater spataal specificlty, and because they frequently are more of the deterministic than of the index type offer the potential of greater forecasting power under extreme conditions Finally, the combination has an especial appeal because to some degree it appears that each needs the other to reahze its maximum contribution Despite these attractive aspects of the eomblnatlon, some cautaon is warranted for several reasons. The substantial inherent difficulties m distributed parameter modehng are now surfacing vcadely (for watershed modehng for example, see Overton and Meadows, 1976, Lmsley,
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j E ESTES, J R JENSEN AND D S SIMONETr
1976, and Peck, 1976). Even simple in- concerned with water d e m a n d and dex models may skim off the bulk of the stress, (3) agrometeorologlcal models benefits from modehng because of sys- within which remote sensing performs a tem conservahon and averaging. Also the confirmahon, weighting, or cahbratlon reduchon m the uncertainty from that funchon, and (4) descnptive and predlcachieved by index models--through use hve models of land-use change based on of distributed parameter m o d e h n g - - m a y frequent updating. A review of the previous list will reveal be insufficient to warrant the conversion costs and other expenses revolved In hy- a serious gap m the modeling realm. drology, many professionals see remote Other than crop yield, note the senous sensing as being of only shght value m lack of attempts to incorporate remote well-gauged watersheds but do expect ~t sensing into economic modeling. The to be of considerable use in ungauged primary reason for this is that economic geographers have the census available watersheds. A third recent development which which is a first-rate source of informabegs for incorporation of both remote tion Therefore, why be concerned with sensmg data and use of chstnbuted- remote sensing? We suggest that satelhte parameter modehng is that of geobase remote sensing could perform the imreformation systems (Bryant, 1976, portant role of "unpacking" aggregated census data in both space and time For Bryant and Zobnst, 1977; Slmonett et al (eds), 1978, Shelton and Estes, 1979). Un- instance, a researcher may be using a til recently, geobase information systems population density stahstac for a given essentially lacked data of a quahty, quan- census tract wbach is spatml m nature but hty, and hmehness to adequately dnve highly aggregated By incorporating hetthe systems Dependmg on the apphca- erogeneous land-use data derived from tlon, remote sensing may provide data m remote sensing, ~t ~s possible to unpack a format and time framework compatible the census tract data allowing the researcher to know which spatial regions with the range and consistency needed However, there are many difficulties stdl wathm the tract account for most of the be to resolved if the incorporation of vanance. In effect, both the census and remote sensing ~s to have a slgmficant remote sensmg data become calibrated and may be used with change detection impact on geographic systems analysis First, one of the major dlscovenes in and future land-use modeling to provade workang with Landsat data has been that a variety of socml and economic statistics even at ~ts current 80-m spatml resolu- of importance to economic geographers tion, it provides data of such spahal de- In this respect it is important for ecotad and specificity that exlstang models nomic geographers to note that the cannot accommodate the data. Among census itself is presently funding studies the areas where mvestlgators are now to test how the mergang of Landsat and tmprowng existing models to incorporate census data can improve the latter the remote sensing data are (1) hydroThus, we find that remote sensing may logic models incorporating landcover and play an integral part in systems analysis land use data, (2) agricultural models whereto it may funchon as a "hnch pro"
IMPACTS OF REMOTE SENSING
71
At the 1964 conference sponsored by the Nahonal Academy of Science/National Research Councd, (Nahonal Academy of Scwnce Nahonal Research Councd, 1966) Peter Goshng described an "air of enthusiasm which msplred panel members to work eagerly and nnagmatwely on thetr respectwe reports." This meeting brought together at a cntacal early stage m the Umted States space program the talents of a number of chstmgmshed geographers to make recommendahons on the potential of the newly developing field of spacecraft remote sensing as a tool for the geographer Statements at this meeting such as "The opportumty to obtain synophc, regularly repeated vaews of the whole earth and the changang surface of the lands and seas wdl have a profound effect on the growth and mternatlonahzatlon of geographic sciences," dlustrate the potenIn Conclusion: A Look hals recogmzed by these leaders in the at The Future field (National Academy of Science Nahonal Research Councd, 1966). It is a H V. B. Khne, Jr, writing on the pity that more of the attendees did not prospects for air-photo mterpretatmn m mallntaln their enthusmsm! American Geography Inventory and ProThe exploltahon of the improved or spect (m James and Jones, 1954), quotes umque mformatmn avadable to the geogJohn E Kesseh as saying, "Only in de- rapher wa the apphcatmn of remote senspartments so sufficiently staffed to con- ing techmques has barely begun Yet, sider all parts of the geographic field can when thoughtfully analyzed it can be it be expected that air photography has seen to provide the geographer with found, or may find, its due conslderataon slgmficant xmprovements m the quanhty, as a research field" Furthermore, the quahty, and hmehness of data reqmred student " • is mchned to neglect field As more geographers become aware of and laboratory courses which prowde a the slgmficant lmphcatlons of remote training in the gathenng and lnterpreta- sensing for prowchng such data, the true hon of mformahon, hoping that his prob- impact of this techmque m the dlsclphne lem wdl take care of ~tself when the hme wdl be felt Remote sensmg, hke cartogfor Independent research arrives " It is raphy, is approaching such a state of hoped, m geography flus sltuahon is technology and body of coherent knowlchangmg edge and theory that it can almost be
to interface meteorologacal, social, economic, and physical data together for effectwe modehng purposes As previously noted, however, cartographers and physical geographers currently account for the most serious basic and apphed remote sensing research Economic and regional geographers, on the other hand, are largely lguonng remote sensing technology The burden falls heavily, therefore, on those geographers who are cartography/remote sensing technologists to interface wath the regaonal and economic geographers and acquaint mdlwduals m these important areas of the potentmls offered by remote sensing technology. In this manner, our colleagues may begin to incorporate the mformahon derived from the analysis of remotely sensed data into their research.
72 vaewed as a chsciphne m and of itself. What is requtred to increase the tmpact of remote sensing m geography is a concerted effort on the part of geographers and others who speclahze in remote semsng to c o n d u c t their research thoughtfully so as to more effechvely impact thetr dasclphnes. The quanhtatave revolution of the late fifties and stxhes m geography taught geographers to be more ngorous m our approach to data analysis. The remote sensing revolution is now showang a growing number of geographers that we can be more rigorous in our methods of data collection. This is particularly true with respect to the collectaon of data on spatmlly distributed p h e n o m e n a By comblmng advanced data collection procedures Incluchng remote sensing wath rigorous data analysis techmques and employing tins synergasm to the modehng of spatially chstnbuted biophysical and socioeconomic phenomena the true potential of geographical analysis comes closer to reahzahon. Yet, just as the acceptance of the quanhtahve mathematical school of geographical analysis was slow m coming and severely cnhclzed by the "old guard," so too is remote sensing feehng this same type of restraint as we attempt to awaken geographers to Its capablhhes. Remote sensing is a reahty within geography whose tune has come It is too powerful a tool to be ignored in terms of both its information potential and the logic implicit in the reasoning process employed to analyze the data W h e n allied wath the traditional cornerstone of geography, 1 e., cartography, in its new dagatal ratment, the two techmques can go far beyond being mere technologies W e predict they could change our perceptaons, our methods of data analysis,
j E ESTES,j R JENSENAND D S SIMONETF our models, and our paradigms. This process to some extent has already begun on the physlcal/envaronmental side of the ¢hsclphne but the full potential for corssfertdlzmg synergasm which can enrich the whole field of geography wdl be realized only if a larger share of the regtonal, economic, and social geographers make some use of the techmque, and only if geographers aggressively seek the research funchng required to demonstrate the magnitude of the promise held in remote sensing m these areas
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IMPACTSOF REMOTESENSING 53 McDonnel, M. J, and Lewis, A J (1978), Ship Detection from Landsat Imagery, Photogram Eng Remote Sens 44 297-301 54 Estes, J. E , Mel, M R, and Hooper, J O (1977), Measuring sod moisture with an atrborne imaging passwe microwave rachometer, Photogram Eng Remote Sens 44 1273-1281 55 Welch, R (1977), Progress m the specfftcataon and analysis of image quahty, Photogram Eng Remote Sens 43 709-719 56 Welch, R., and Lo, C P (1977), Height measurement from satellite images, Photogram Eng Remote Sens 43 1233-1242 57 Tmney, L. R, Jensen, J. R., and Estes, J E (1977), Mapping archeology sites from historical photography, Photogram Eng Remote Sens 43 35-44 58 Thomas, I L, Lewis, A J, and Chmg, N P., Snowfield assessment from Landsat, Photogram Eng Remote Sens 44 493-502. 59 Lewis, A J (1977), Coastal mapping with Radar, G eosci Man, 43 239-247 60 Klemas, V, Bartlett, D, and Rogers, R (1975), Coastal zone elasslficataon from satelhte imagery, Photogram Eng. Remote Sens 41 499-513 61 Seevers, P M, Peterson, R M , Mahoney, D J, Moroney, D G, and Rundqmst, D C (1975), A wetlands inventory of the State of Nebraska using ERTS-1 maagery, Remote Sensing of Earth Resources, Vol 4, Umv of Tenn Space Inst, pp. 281-292. 62 Rehder, J B (1976), Changes m landscape due to strip immng, ERTS-1A New Window on Our Planet, U.S Geological Survey Professional Paper 929, Government Printing Office, Washington, D C, pp 252-257
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Symposium on Remote Sensing of Enmronment, ERIM, Ann Arbor, MI, pp 373-382 72 Lo, C P, Pannell, C. W , and Welch, R. (1977), Land use changes and city planrang m Shenyang and Canton, Geograph Rev, 67.268-283 73 Institute of Science and Technology (1963), Remote Sensing of Environment, Final Report, ONR Contract No. NOnr 1224 (4r), 71 pp 74 Holz, R. K (1973), The Surve, llant Sc,ence Remote Sensing of Entnronment, Houghton Mfffhn Pub., Atlanta, 390 pp 75 Estes, J. E , and Senger, L. W (Eds) (1974), Remote Sensing Techmques for Entnronmental Analys,s, Hamdton Pubhslung Company, Santa Barbara, CA, 340 pp 76 Rudd, R D (1974), Remote Sensing A Better Vww, Duxbury Press, North Scltuate, MA, 135 pp 77 Lmtz, J, Sr, and Slmonett, D S. (1976), Remote Sensing of Env,ronment, Ad&son-Wesley Pubhshmg Co., Reading, MA, 694 pp 78 Pachason, B (Ed) (1978), Introduct,on to Remote Sensing, Kendall-Hunt, Clucago, 496 pp. 79 Reeves, R G (Ed m Ctnef) (1975), Manual of Remote Sensing, Amer. Soc. Photogram., Fails Church, VA, 2144 pp. 80 Pdchason (1978), op c,t, footnote 48 81 Ford, K, ed (1979), Remote Sensing for Planners, Center for Urban Pohcy Research, Rutgers Umv., NJ, 219 pp 82 Anderson, J R, Hardy, E E., Roach, J T , and Wltmer, R E (1976), A land use and land cover classffacahon system for use with remote sensor data, U S Geolog Survey Professional Paper, 26 pp 83 Anderson, J R (1977), l_and use and land cover changes--A framework for momtonng, J Research U.S Geolog. Survey 5 142-152
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pmg by Interpretation of Landscapes from Satelhte Imagery, Ph D. Dlssertataon, Dept of Geography, Umv of Kansas 96 Harwood, P, Finley, R, McCulloch, S., Mahn, P A., Schell, J. (1977), Development and apphcataon of operational teehmques for the inventory and momtormg of resources and uses for the Texas coastal zone, Final report, Goddard Space Fhght Center, Greenbelt, MD, Vol 1, 237 pp. 97 Moram, S A, and Wdlmms, D L (1973), Esttmates of winter wheat yaeld from ERTS-1, Proceedings of the Third
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