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Comparative economics and analytical expansion
Photogrammetria, 38 (1982) 35--56 Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
35
COMPARATIVE ECONOMICS AND ANALYTICAL EXPANSION
BERNARD L.Y. DUBUISSON Ecole des Travaux Publics, 20 Avenue Paul Appell, 75014 Paris (France)
(Received August 28, 1980; revised and accepted February 25, 1981)
ABSTRACT Dubuisson, B.L.Y., 1982. Comparative economics and analytical expansion. Photogrammetria, 38: 35--56. This paper presents an economic analysis of the various phases of production, namely: conventional graphic analog photogrammetry, analog photogrammetry equipped with computer-aided peripherals and plotting table, and analytical photogrammetry, together with a comparative synthesis of studies of productivity, accuracy and economics in the various fields. Conclusions are drawn concerning stimulating the development of analytical means for certain economic requirements.
INTRODUCTION Descriptive and q u a n t i t a t i v e m e t r o l o g y is at t h e origin o f all decisions; t h e r e is n o t h i n g n e w in this s t a t e m e n t , f o r " m a s t e r s u r v e y o r s " have always b e e n with us. T o d a y , h o w e v e r , t h e s c o p e o f r e q u i r e m e n t s has b e c o m e m u c h greater, b o t h in t h e spatial a n d m a c r o s c o p i c and m i c r o s c o p i c realms: m a p m a k i n g and cadasters are as m u c h c o n c e r n e d as biological and industrial m e t r o l o g y . This n e w s i t u a t i o n reveals t h e a n a c h r o n o u s precariousness o f t h e means o f m e a s u r e m e n t c o n s i d e r e d u p t o n o w as " c o n v e n t i o n a l " . N e w t e c h n o l o g i c a l d e v e l o p m e n t s have e m e r g e d , h o w e v e r in t o p o g r a p h y and land surveying, b o t h in e l e c t r o - m a g n e t i c distance measuring and in c o m p u t e r based m e t h o d s used f o r o t h e r activities. This e v o l u t i o n was so p r o n o u n c e d t h a t it was believed at o n e t i m e t h a t t h e growing c o n t r o l exercised b y p h o t o g r a m m e r r y o v e r m e a n s o f measuring o n t h e g r o u n d w o u l d b e c o m e less significant. At this p o i n t t h e r e began t h e d e v e l o p m e n t o f analytical p h o t o g r a m m e t r y w h o s e universal a p p l i c a t i o n is t h e o n l y o n e capable o f satisfying o u r n e e d s in t h e m o s t i m p o r t a n t fields w h e r e m o d u l a r i t y , p r o d u c t i v i t y and a c c u r a c y are increasingly d e m a n d e d o f m e a n s o f m e t r o l o g y and are d e t e r m i n i n g f a c t o r s ; f o r e x a m p l e , scientific a n d t e c h n i c a l d e v e l o p m e n t s linked w i t h space research, civil engineering a n d i n d u s t r y . In general, a n d t h r o u g h o u t a l m o s t t h e e n t i r e w o r l d , p h o t o g r a m m e t r i c needs 0031-8663/82/0000--0000/$02.75 © 1982 Elsevier Scientific Publishing Company
36 are satisfied b y " a n a l o g " instruments, but their operating principle leads to all sorts o f limitations which render t h e m inadequate for the fulfillment of numerous present-day requirements, such as the development of automation of measurements which has now become an obvious necessity in all fields. On the other hand, there appears to be no limitation on the use of analytical plotters (AP's) as studied herein with particular attention to the Traster System. Here all simulations, transformations and spatial measurements are mathematical; adaptations to specific production requirements are assured by specific software which may be integrated into the system's overall software in order to solve a given problem. The use of AP's does not really require professional qualifications in photogrammetry and t h e y m a y be quite readily used by the practitioner himself to make his own measurements: the engineer-builder, architect or doctor, for example. Accuracy has been doubled (in the particular case of Traster), while production is improved at a ratio which the present report will define, with correlative influence on savings in production costs. Today, everyone admits t h a t the most productive, accurate and universal application in p h o t o g r a m m e t r y for delicate work can only be analytical, but other factors also become evident: (a) Most photogrammetric work is still involved with mapmaking and cadasters. (b) Practically all photogrammetric instruments in use are analog. They are complemented often by electronic digital acquisition in the model, a function for which t h e y have n o t always initially been designed. They then perform what we shall call -- in this study . . . . conventional" analog photogrammetry. (c) The most recently designed analog instruments facilitate the use of certain a u t o m a t e d functions permitting reducing the importance of labor. However~ t h e y remain limited as to their fields of use and accuracy because of their very principle: in the present study, we shall call their function "advanced" analog p h o t o g r a m m e t r y . Industrialized countries are obliged to gradually renovate that part of their range o f instruments which has become technically outdated. Third World countries must be equipped with new cartographic means in order to acquire cadastral and mapmaking a u t o n o m y , the natural complement of territorial appropriation. (d) The bitterness of competition resulting from the economic situation requires the use of fast, flexible, accurate and economical metrological means, both in cartography and industry. The pragmatism of public officials, however, cannot be satisfied by assertions, however evident t h e y may be. They demand that costs and profits anticipated in such development be calculated so as to make the best adaptation of investments to the case under consideration. The diversity of possible metrological operations does not simplify this sort of economic study, the less so since analytical plotting instruments alone are
37
capable o f performing functions previously performed b y several different, complementary items of equipment; as an example, one might mention the fields of aerotriangulation, graphical and digital plotting, a u t o m a t e d draughting, calculations, etc. As such an economic survey cannot reasonably cover all such work, the present study is confined to a field of photogrammetry in c o m m o n use and where rates are c o m m o n practice: large-scale drawings for development of the French territory. These involve results from photogrammetric surveys made b y a group of agencies over scores of years and gradually brought to their most efficient level of productivity via analog photogrammetry equipped with instruments in current use up to 1975. In order to be exhaustive, however, this study had to be carried further to include the most recent analog instruments, which, through electronic adaptations, improve savings in production costs. Analytical p h o t o g r a m m e t r y will thus be compared successively with: (a) "conventional" analog photogrammetry; and (b) "advanced" analog photogrammetry*. From these two financial and productivity comparisons conclusions will be drawn in which the advantages of the analytical process will be reduced, in principle, to a minimum. In fact, the doubling of analytical accuracy will lead to an evolution of the use m e t h o d o l o g y which will accentuate its productivity, b u t which has not been taken into consideration in this study. 1. P R I N C I P L E S O F THE S T U D Y A N D C O N V E N T I O N A L BASIC E L E M E N T S
1.1. General principles o f the comparative study The basis of the study is the productivity and costs of "conventional" analog photogrammetry the various phases of which are priced at rates which are very well known, and which is carried o u t for public agencies b y established firms. Economies achieved with respect to these rates b y "advanced" analog photogrammetry and b y analytical photogrammetry result from technological advantages and from reduced labor requirements for the t y p e of instrument usually used for a well-defined function. Furthermore, it seemed o p p o r t u n e in the present study to distinguish between the public sector (public cartography and cadaster services etc.) and the private sector (industrial or engineering agencies); the former users invest periodically but do not deduct the annual amortization of their equipment in their public accounting (in general), whereas the private sector, obviously~ is obliged to do so. In the latter case, linearly proportional amortization in time *We shall include in this c a t e g o r y t h e use o f i n s t r u m e n t s f r o m t h e p r e c e d i n g g e n e r a t i o n w h i c h have b e e n e q u i p p e d by t h e i r users w i t h accessories or p e r i p h e r a l s allowing t h e s a m e general uses a n d p e r f o r m a n c e as m o r e r e c e n t analog i n s t r u m e n t s .
38 has been taken into account, but w i t h o u t including interest rates. Finally, estimates have been made on the basis of an annual (conventional) labor period of 1880 working hours covering, on the one hand, one shift per day and~ on the other, two shifts per day. Where cost estimates are required, t h e y have been drawn up in U.S. dollars, w i t h o u t presuming t h a t t h e y apply strictly to the U.S.A. Employees' benefits contributions linked with labor costs, as well as overhead and profits and maintenance, have been estimated in an identical manner for each t y p e o f p h o t o g r a m m e t r y under consideration. These comparisons have also involved amounts devoted to investments (and their amortizations); these latter obviously vary from one country to another because of the diversity of taxes and customs duties, as well as m o n e t a r y fluctuations (comparisons in the present study refer to March, 1979). Since the conclusions will, however, concern only the relationship between costs and productivity of analog plotters and those of analytical (Traster) plotters, results -- as a basis of comparison -- will remain coherent for the various countries, although each elementary value expressed may be contested for a given place or a given circumstance. Because of the multiple nature of the necessary parameters involved this economic study is quite complex; it thus seemed useful to indicate at the beginning the references for tables of results: (2.2.2), (2.2.3), and (2.2.4). We should also mention that, as an item in the final result, the analytical method represents an e c o n o m y of 21% over the analog m e t h o d with tripled accuracy in the large-scale plans studied. These figures, however, will be improved by using an overall methodology adapted to the analytical method.
1.2. Basic price elements for various types of photogrammetry 1.2.1. Hourly labor expenditures for plan-producing agencies (weighted hypothetical values) -- stereoplotter operator: 20.1 US$; draughtsman-assistant: 12.8 US$ -- giving the total labor cost calculated in various cases (see Tables 2.1.2, I, II and III): "1 technician" = 1 plotter only : 20.10 US $ "1.1 technician" = 1 plotter + 1/10th time for 1 assistant: 21.38 US $ "1.5 technician" = 1 plotter + 1/2 time for 1 assistant : 26.50 US $ "2 technicians" = 1 plotter + 1 assistant : 32.90 US $ 1.2. 2. Hourly amortization and main tenance costs (see Table 1.2.2) 1.2.3. Operating costs. Overall costs, unforeseeables, margins or profits are estimated for both public and private sectors at 80% of overall personnel expenditures. 1.2.4. Nature o f expenditures in both private and public sector accounts. We
39
T A B L E 1.2.2. Hourly amortization and maintenance costs Equipment
a Amortization costs
b Maintenance costs
1 2 Presumed 1 2 shift shifts purchase shift shifts price US$ Over 8 years: 5% per year
Type No.
Stereoplotter specification ("advanced" analog)
1
Analog, 2nd order, usable for small scale with digitization and recording
80,000
5.32
2.66
2.13 1.07
2
Analog, 2nd order, usable for small scale with digitization, graphic console of central computer for eventual automatic mapmaking
110,000
7.31
3.66
2.93 1.47
3
Analog, 1st order with co-ordinate recording, tape, semi-automatic table
150,000
9.97
4.99
3.99 2.00
4
Other analog, 1st order with calculation model co-ordinates and tape recording and semi-automatic table, T.V,
202,000
13.43
6.72
5.37 2.69
5
1st order as No. 4 in "digital system", in geographic co-ordinates coded for au~omatic mapmaking
215,000
14.30
7.15
5.72 2.86
Over 5 years: 8% per year 6
AP's: Traster example with table and 64K disc, digital and graphical process in geographic co-ordinates of points
210,000
22.34 11.17
8.94 4.47
assume t h a t t h e cost o f an o p e r a t i o n will be e s t i m a t e d b y a c c o u n t s for t h e following items: (a) f o r p u b l i c s e c t o r : l a b o r (1.2.1); m a i n t e n a n c e (1.2.2.b); o p e r a t i n g costs (1.2.3). (b) f o r private s e c t o r : l a b o r (1.2.1); a m o r t i z a t i o n (1.2.2.a); m a i n t e n a n c e (1.2.2.b); o p e r a t i n g costs (1.2.3). F o r each t y p e o f p r o d u c t i o n , and w h a t e v e r t h e t y p e o f p h o t o g r a m m e t r y involved, e s t i m a t e s will be m a d e f o r o n e shift per d a y , t h e n f o r t w o . In all cases, p r o d u c t i v i t i e s f o r a n a l o g p h o t o g r a m m e t r y will be applied (2.1.1 .II.a, b a n d c). T h e s t u d y will t h e n be c o n t i n u e d f o r a n a l y t i c a l p h o t o g r a m m e t r y using t h e same cases a n d t h e same w o r k i n g p r o c e d u r e , b u t w i t h its o w n p r o d u c t i v i t y .
40
2. ECONOMICANALYSES OF PRODUCTION
2.1. Economic study of analog photogrammetry Two facets will be studied: (a) basic statistical productivity in "traditional" analog photogrammetry which will then be transposed into "advanced analog"; and (b) significant examples from the point of view of productivity and unit prices of cartographic production. These two points will be studied successively in the different versions with respect to: (a) aerotriangulation; (b) model orientation; and (c) detail plotting, small and large scale.
2.1.1. Basic statistical productivity in "conventional" and "advanced" photogrammetry I. Aerotriangulation. All operations included: 2 h 50 min per stereo pair, i.e., 2.8 pairs per 8-hour day.
H. Plotting. Graphical and digital. These productivity values are not scores achieved over short periods of time, but are taken from statistical results of bid proposals filed by highly-qualified
TABLE 2.1.1.II a. T i m e r e q u i r e d f o r f o r m a t i o n a n d o r i e n t a t i o n m o d e l Formation and numerical orientation model Setting again a model Format, ion and graphical orientation model .................................................................................
1 h 20 rain 40 rain 2 h 5 rain
Average duration
1 h 22 rain
Scale
Planimetry of density of residential urban suburb Rate per dm 2
Rate per stereopair
Altimetry: mountain,
Rate for 1 point
Rate per linear (din) of contour
1 1 . 3 3 sec
10.8 rain
11.5
10.8 min
average slopes 15%
Rate per dm 2
Rate per stereopair
b. C o m p i l a t i o n t i m e in g r a p h i c a l p l o t t i n g Plan 1 : 2000 Photo 1:8000
1 h 23 rain
Map 1 : 25,000
3 h
5 rain
27 h 4 0 rain
7 h 35 rain
c. T i m e r e q u i r e d f o r d i g i t a l p l o t t i n g p e r f o r m e d Plan 1 : 2000 Photo 1 : 8000
1 h 45 rain
34 h 10 rain
sec
for automated
2 h 40 rain
18h
54 h
44h
draughting and creating data storage files
1 3 . 9 7 sec a
aIncluding conventional point-coding time. bAltimetry defined by interpolations of altimetric points or by D T M
5.08 rain b
profiles.
6 h 46 rain b
41
agencies in response to calls for bids for large projects. Obviously, they include normal coverage for risks involved in technological production with its monitoring and corrections. These estimates result from 15 years of production; average j o b size was 25 stereo models for each job, with 300 jobs per year. Modifications achieved via "advanced" stereoplotters have not been counted in productivity b u t only in unit prices for certain production operations; these costs are sometimes reduced because of the decrease in the number of technicians assigned (statistically) to each instrument. This factor will appear in the study of "significant examples".
2.1.2. Significant examples of productivity and costs for a stereo pair in analog photogrammetry (see Table 2.1.2) 2.2. Economic study o f analytical photogrammetry 2.2.1. Conventional bases for estimates Although the study of the yield of analog plotters could be based on longestablished practices, this is evidently not the case with analytical plotters; Traster, in particular, on which this analysis is based, has not been in use for long nor used regularly in intensive mapmaking production which can be statistically equivalent to that of analog instruments. In an initial phase, and on the basis of acquired experience, one must, therefore, be content with evaluating the logical increase in productivity obtained in the various operating phases of analytical practice. Special attention will be given to aerotriangulation aspects as well as model formation and orientation, which can be most readily estimated. Most of all, however, attention will be focussed on the general conditions for measuring detailed surveys on the instrument. Economies achieved will thus be analyzed successively in: (a) aerotriangulation; (b) model formation and orientation; and (c) operations involving plotting of small- and large~cale details for b o t h 1 and 2 shifts per day. One can accept, arbitrarily and for the needs of a rough evaluation of some estimates, that a single analytical stereoplotter performs all the photogrammetric operations needed for 60 stereo pairs during the 1880 annual working hours o f one work shift. In the case of Traster, all operations are performed b y a single technician, the plotter. It is therefore interesting to recall the estimates made in § 1.2.1. to 1.2.4. above, dealing with various costs constituting overall production expenditures. For an AP such as Traster, we have, in US dollars:
Aerotriangulation
Nature
3
Equipmerit type number (see 1.2.2.)
2 h 50 m i n
Duration of operation
Formation model a n d graphical orientation
D
Small scale, average costs:
1
Settingagain a model
C
1
1
Formation model and numerical orientation
B
Small scale survey, 1 : 25, 000
2 h 05 m i n
40 min
1 h 20 m i n
II. M o d e l - - Relative a n d a b s o l u t e o r i e n t a t i o n
A
I.
No.
Operation
C.Pub. A.Pub. C.Pri. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
"Con." "Adv." Publ. Pri.l
1.5 1.5 1.5 1.5
1.5 1.5 1.5 1.5
1.5 1.5 1.5 1.5
1
No. o f technicians
48.77 51.43 48.77 51.43 48.77 51.43 48.77 51.43
49.83 55.15 49.83 55.15
48.77 51.43 48.77 51.43
38.18 43.17 38.18 43.17
2 shifts
49.83 55.15 49.83 55.15
49.83 55.15 49.83 55.15
40.17 50.14 40.17 50.14
1 shift
C o s t s per hour
67.82 67.82 75.07 75.07
103.81 114.90 103.81 114.90
33.22 36.77 33.22 36.77
66.44 73.53 66.44 73.53
113.81 142.06 112.81 142.06
1 shift
66.38 66.38 70.00 70.00
101.60 107.15 101.60 107.15
32.51 34.29 32.51 34.29
65.03 68.57 65.03 68.57
108.18 122.31 108.18 122.31
2 shifts
Co~t~ production
T A B L E 2.1.2. Significant examples o f productivity and costs for a stereopair in analog p h o t o g r a m m e t r y
b~
NaCre
Setting again a model
Formation model and graphical orientation
F
G
3
3
3
Equipment type number (see 1.2.2.)
2 h 05 rain
40 min
1 h 20 rain
Duration of operation
1.5 1.5 1.5 1.5 1.5 1,5 1.5 1.5
C.Pub. C.Pri, A.Pub. A.Pri. C.Pub. C.Pri. A.Pub. A.Pri. C.Pub. A.Pub. C.Pri. A.Pri.
1.5 1.5 1.5 1.5
No, of technicians
C.Pub. C.Pri. A.Pub. A.Pri.
"Con." "Adv." Fubt. Pri.l
51.69 61.66 51.69 61.66
51.69 61.66 51.69 61.66
51.69 61.66 51,69 61.66
1 shift
49.70 54.69 49.70 54.69
49.70 54.69 49.70 54,69
49.70 54.69 49.70 54.69
2 shifts
Costs per hour
70.36 70.36 83.93 83,93
107.69 128.46 107.69 128.46
34.46 41.11 34.46 41.11
68.92 82.21 68,92 82.21
1 shift
67.65 67.65 74.44 74.44
103.54 113.94 103.54 113.94
33.13 36.46 33.13 36.46
66.27 72.92 66.27 72.92
2 shifts
Costs production
1 Abbreviations in this and following tables signify: C. = " c o n v e n t i o n a l " analog p h o t o g r a m m e t r y ; A. = " a d v a n c e d " analog photogrammetry; Pub. = public sector; Pri, = private sector.
costs:
Large scale, average
Formation model and numerical orientation
E
Large scale survey, 1 : 2 0 0 0
No.
Operation
TABLE 2.1.2. (continued)
2.1.2. (continued)
Nature
Equipment type number
Duration of operation per d m 2 a n d per survey p o i n t
1
1
Planimetry (peri-urban)
Altimetry (mountain)
Planimetry (peri-urban)
Altimetry (mountain)
J
K
3
3
Large-scale survey (1 : 2000)
H
Small-scale survey (1 : 25,000)
2 h 40 m i n / d m :
11.33 s e c / p o i n t
1 h 23 m i n / d m :
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri. 1.5 1.5 1.1 1.1
2 2 1.1 1.1
1.5 1.5 1.1 1.1
C.Pub. C.Pri. A.Pub. A.Pri.
18 h / d m 2
No. technicians employed
2 2 1.1 1.1
C.Pub. C.Pri. A.Pub. A.Pri.
3 h 05 m i n / d m 2 C.Pub. C.Pri. 11.5 s e c / p o i n t A.Pub. A.Pri.
G R A P H I C A L P L O T T I N G (see Table 2.1.1.IIb)
No.
Operation
III. P l o t t i n g details in analog p h o t o g r a m m e t r y
TABLE
61.22 66.21 40.48 45.47 49.70 54.69 40.48 45.47
51.69 61.56 42.47 52.44
48.77 51.43 39.55 42.21
49.83 55.15 40.61 45.93
63.27 73.38 42.47 52.44
53.29 62.95 39.55 42.21
2 shifts
61.35 66.77 40.61 45.93
1 shift
Costs p e r hour
137.84 164.43 113.25 139.84
87.52 101.23 58.75 72.54
896.94 992.70 730.98 826.74
189.16 205.57 125.21 141.62
1 shift
132.53 145.84 107.95 121.25
84.69 91.59 56.00 62.90
877.86 925.74 711.90 759.78
164.31 194.10 121.95 130.15
2 shifts
per d m ~ o n m a p
-----
0.199 0.24 0.136 0.165
-...... ---
0.196 0.213 0.13 0.147
1 shift
0.193 0.208 0.127 0.143
0.17 0.201 0.126 0.135
2 shifts
per p o i n t s u r v e y e d
P r o d u c t i o n costs, u n i t costs c o u n t e d
Nature
Equipment type number
Duration of operation per dm 2 and per survey point
No. technicians employed
C.Pub. C.Pri. A.Pub. A.Pri.
L
5
5
Planimetry (peri-urban)
Altimetry (mountain) DTM; supplementary points
Large-scale survey (1 : 2000) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5
1 h 45 m i n / d m 2 C.Pub. C.Pri. 13.9 sec/point A.Pub. A.Pri. 5 min 18 sec/dm 2C.Pub. C.Pri. 13.9 sec/point A.Pub. A.Pri.
DIGITAL PLOTTING (for automatic cartography) (see Table 2.1.1.Iic)
No.
Operation
T A B L E 2.1.2. (continued)
50.56 57.77 50.56 57.77 50.56 57.77 50.56 57.77
53.42 67.72 53.42 67.72
2 shifts
53.42 67.72 53.42 67.72
1 shift
hour
Costs per
4.52 5.73 4.52 5.73
93.48 118.51 93.55 118.51
1 shift
4.28 4.89 4.28 4.89
88.48 101.10 88.48 100.99
2 shifts
per dm 2 on map
0.207 0.263 0.207 0.263
0.207 0.263 0.207 0.263
1 shift
0.196 0.224 0.196 0.224
0.196 0.224 0.196 0.224
2 shifts
per point surveyed
Production costs, unit costs counted
46 TABLE 2.2.1. Overall costs of hourly production
One-shift operation Two-shift operation
Public sector
Private sector
45.12 40.65
67.46 51.82
2. 2.2. Aerotriangulation Judiciously adapted to the various operational phases of aerotriangulation, analytical plotting permits of considerable simplification of previous routines imposed b y conventional methods. It is not o p p o r t u n e to give details of this procedure here, although several aspects may be mentioned: (1) Following a computer-slaved order to shift the exposures, possibility of: (a) automatic plotting on the image of a transfer point already used on the stereo-pairs and sometimes contiguous strips, with help of slaved electronic removal system; (b) definitive formation of models during the acquisition phase in the real-time strip aerotriangulation. (2) Thanks to the automatic servo-travel, checking coherence and accuracy of transfer points used on a model before any insertion into aerotriangulation calculations. (3) Possibility of real-time sequential calculation of aerotriangulation for each strip as acquisitions progress. (4) Possibility of ensuring definitive correction in a few minutes of the block of strips on the computer (Traster computer) in semi-deferred time. Finally, m e m o r y storage of definitive results: transfer point numbers, exposure co-ordinates, corrected space co-ordinates, and m e m o r y storage of parameters of the various orientations (internal, relative, absolute) for each stereo pair. All these possibilities eliminate the long and delicate organizing work preceding measurements, with the familiar accessories for pin-pointing and transferring points. The work involved in final storage of results in archives also becomes unnecessary. The reliability of such results is optimal, because each detail operation is checked in real time, thus permitting, if necessary, immediate touching-up. It is thus quite evident that productivity is considerably increased since the time gained is estimated at 80% with respect to previous methods. In the various cases considered, it is advisable to calculate anticipated savings in aerotriangulation on an analytical plotter (Traster, for example); it should be done for one pair, 60 pairs (which, hypothetically, can be completely processed annually b y a single instrument) and, finally, for a period of five years {within the same hypothesis).
47 TABLE 2.2.2 Savings (in US dollars)
Savings achieved on one stereo pair Savings achieved on 60 stereo pairs Savings achieved over 5 years
Case of a public service
Case of a private agency
1 shift per day
2 shifts per day
I shift per day
2 shifts per day
91.05 5,463.60 27,315.00
86.54 5,192.40 25,962.00
113.65 6,819.00 34,095.00
97.85 5,871.00 29,355.00
2. 2.3. Formation and orientation models A trained operator takes 10 rain to carry out a complete setting up operation for a stereo pair; this value must be compared with the average time spent in analog procedure, i.e. 82 min (Table 2.1.1. II). In addition, when orientation has been set previously during aerotriangulation, it is indispensable to set one of the pairs anew on AP's (Traster, for example) in order to exploit details of plotting; this "partial orientation" requires only 4 minutes per stereo pair, whereas 40 rain are required in analog p h o t o g r a m m e t r y for a similar case of setting up a model again. In fact, all aerotriangulation parameters are stored in the m e m o r y and it suffices to extract them. To obtain a simple overall comparison permitting of expressing sums economized on analytical orientations, we shall use the hypothesis of equal distribution of the various types of work previously considered under the heading "small-scale surveys" on the one hand, and "large scale surveys" on the other. (See Table 2.1.2. II, operations B, C and D for small scales, and operations E, F and G for large scales.) In Table 2.2.3, the average cost is shown of orientation of a pair in analog procedure, t h a t in analytical procedure and the savings achieved thanks to the latter for the eight usual cases for such estimates: public sector, private sector, one-shift and two-shift daily work, and finally, small and large scale. 2.2.4. Plotting details AP's have been designed to be used by a single technician, the plotter. He can intervene manually on the co-ordinatograph
5.42
6.02
74.44
67.65
83.93 for o n e pair f o r 60 p a i r s ] y e a r over 5 years
b C
8.99
a
Average overall savings o n o r i e n t a t i o n s c o m e t o 90.5%.
Averages, all scales c o m b i n e d :
70.36
Large-scale survey
8.99
5.42
6.02
66.38
75.07
70.00
67.82
2 shifts
1 shift
2 shifts
1 shift
1 shift
Small-scale survey
1 shift
Publ. s e c t o r
Priv. s e c t o r
Publ. s e c t o r
18,477
18,921
61.59
63.07
6.91
3695
62.23
3784
60.96 64.34
21,153
4230
70.51
74.94
66.08
1 shift
1 shift 61.80
Priv. s e c t o r
Publ. s e c t o r 2 shifts
Savings a c h i e v e d f o r o r i e n t a t i o n o f 1 stereo-pair
6.91
2 shifts
Priv. s e c t o r
Analytical
Analog
2 shifts
Cost of orientation for 1 stereo-pair
Avg. cost of o r i e n t a t i o n for 1 stereo-pair
Average savings a c h i e v e d in o r i e n t a t i o n s ( e x p r e s s e d in US dollars)
T A B L E 2.2.3
19,593
3919
65.31
57.53
63.09
2 shifts
QO
49
Another favorable element lies in the grouping of all controls, thus sparing the operator the need for moving about: these are keys on the control desk, the t u b e for dialogue with the computer, the TV tube and means for removal through the model. Yet another favorable factor is the replacement of the traditional hand cranks for X and Y travel b y a ball moving on an air cushion; after a brief period of adjustment, the operator usually agrees that this latter is better adapted to h u m a n physiology. In this case, Z travel is controlled b y the operator's other hand, rotating a small cylinder and advantageously replacing the customary circular pedal. Since statistics have n o t yet been established for very long operating periods~ one must be content with logical -- slightly subjective -- evaluation in order to estimate productivity gains achieved. One may thus estimate that, under equivalent production conditions, the described features increase productivity in a proportion which might be reckoned very prudently at a minimum of 15% on the best "advanced" analog plotting instrument. The following tables deal with a survey of details using an AP. Table 2.2.4.I gives the cost in US dollars for operations previously dealt with in analog photogrammetry (in 2.1.2.III). Table 2.2.4.II gives savings achieved with respect to conventional and advanced analog procedure. Tables 2.2.4.III and 2.2.4.IV are summaries extracted from the preceding data, enabling analysis of the results.
T A B L E 2.2.4.IV A n o t h e r a s p e c t of f i n a n c i a l savings Averages s u m m e d u p f r o m T a b l e 2.2.4.II as a b o v e b u t w i t h sole r e f e r e n c e t o w o r k in t w o shifts.
conventional analog
Savings in a n a l y t i c a l over advanced analog
Public
Private
Public
Private
+ 24.8% + 38.5%
+ 12.7% + 14.7%
-4.3% + 3.3%
+ 23.3%
+ 31.6%
+ 2.4%
Savings in a n a l y t i c a l o v e r
Graphical plotting: Small scale Large scale
+ 33.4% + 39.4%
Digital plotting: Large scale
+ 36%
I t s h o u l d b e stressed that comparisons herein are m a d e o f costs u n d e r h y p o t h e s e s d e f i n e d a b o v e , b u t in all cases o f detail plotting: (1) s p e e d is g r e a t e r b y 12% in a n a l y t i c a l ; (2) a c c u r a c y is t r i p l e d ; a n d (3) t h r o u g h o u t t h e w o r l d , the normal working day on c o m p u t e r e q u i p m e n t is t w o shifts (i.e. t h e final f i n a n c i a l r e s u l t in the t a b l e above).
Nature
Number type equipment AP's
Duration of o p e r a t i o n for 1 d m 2 and 1 1 point surveyed
Public sector Private sector
No. of technicians 1 shift
Cost per hour
2 shifts
Altimetry (mountain)
I
6
6
Altimetry (mountain)
K
6
6
2 h 16 m i n / d m 2
1 h 10 m i n / d m 2 9.63 s e c / p o i n t
15 h 18 m i n / d m 2
2 h 37 m i n / d m 2 9.77 s e c / p o i n t
Pub. Pri.
Pub. Pri.
Pub. Pri.
Pub. Pri.
1 1
1 1
1 1
1 1
45.12 67.46
45.12 67.46
45.12 67.46
45.12 67.46
40.65 51.82
40.65 51.82
40.65 51.82
40.65 51.82
102.27 152.91
52.64 78.70
690.34 1034.14
118.06 176.52
1 shift
92.14 117.46
47.42 60.46
621.95 792.85
106.37 135.60
2 shifts
dm: on map
. . . . --
0.121 0.]8
---
0.122 0.183
1 shift
L
Altimetry (mountain) supplementary p o i n t s DTM
Planimetry (peri-urban)
6
Large-scale survey (1 : 2000)
4 min 32 s e c / d m 2 11.87 s e c / p o i n t
1 h 29 r a i n / d i n 2 11.87 s e c / p o i n t Pub. Pri.
Pub. Pri.
1 1
1 1
40.65 51.82 40.65 51.82
45.12 67.46 45.12 67.46
3.25 4.86
66.93 100.07
2.93 3.73
60.30 78.87
0.149 0.222
0.149 0.222
0.134 0.171
0.134 0.171
0.109 0.139
---
0.11 0.141
2 shifts
point surveyed
P r o d u c t i o n costs: u n i t costs for: u n i t c o s t s for:
2. D I G I T A L P L O T T I N G c o d e d for a u t o m a t i c c a r t o g r a p h y ( p r o d u c t i v i t y values f r o m Table 2.1.1.Iic increased by 15%)
Planimetry (peri-urban)
J
Large-scale survey (1:2000)
Planimetry (peri-urban)
H
Small-scale survey (1:25,000)
1. G R A P H I C A L P L O T T I N G ( p r o d u c t i v i t y values f r o m Table 2.1.2.b increased b y 15%
No.
Operation
Plotting details in analytical p h o t o g r a m m e t r y
T A B L E 2.2.4.I
¢51 O
Nature
C.Pub. C.Pri. A,Pub. A,Pri.*
Altimetry (mountain)
I
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A,Pri.
Planimetry (peri-urban)
Altimetry (mountain)
J
K
C.Pub. C.Pri. A.Pub. A,Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
Large-scale survey (1 : 2000)
Planimetry (peri-urban)
H
Small-scale survey (1:25,000)
GRAPHICAL PLOTTING
No.
Operation
35.57 11.52 10.98 13.07
34.88 48,59 6.11 --6.16
206.60 -39.44 40,64 -205.40
71.10 29.05 7.15 --37.90
40.39 28.38 15.81 3.79
37.47 44.37 8.58 2.44
255.90 132.89 89.95 -33.07
57.94 58.50 15.58 -- 5 . 4 5
0.078 0.119 0.015 --0.015
--
- -
---
0.074 0.03 0.008 --0.036
2
4
.
8
4
- - 9 . 3
4
30.5
3 . 1
14.6 --
.
44.2 48.4 15.3 3.9
-
9.7
-
- -
0
19.5
25.8
39.9 48 10.4 --8.5
-
0
29.20 14.40 12.60
35.3 30.1 12.8 --4.2
2 shifts
7
0.084 0.099 0.018 0.004
-
23.00 --4.00 5.50
37.6 14.1 5.7 --26.6
1 shift
--
•- -
- -
---
- -
0.06 0.06 0.016 --0.006
2 shifts
1 shift
1 shift
2 shifts
per d m 2 o n m a p
per point surveyed
per d m 2 on m a p
- -
- -
--
- -
- -
--
- -
43.5 47.6 14.2 2.8
--
---
--
35.3 29.9 12.7 --4.4
2 shifts
(continued)
40.4 49.6 11 --9 --
- -
----
37.9 14.1 6.2 --24.5
1 shift
per point surveyed
S a v i n g s o n u n i t e x p e n d i t u r e s (%)
Savings in c o s t s ( U S $ o n u n i t v a l u e s )
Savings a c h i e v e d via a n a l y t i c a l over " c o n v e n t i o n a l " a n d " a d v a n c e d " a n a l o g ( w i t h t r i p l e d a c c u r a c y a n d s a m e m e t h o d o l o g y )
T A B L E 2.2.4.II
Oa
Nature
C.Pub. C.Pri. A.Pub. A.Pri.
Altimetry (mountain) supplementary p o i n t s DTM
C.Pub. C.Pri. A.Pub. A.Pri.
2.48 0.87 1.27 0.87
26.55 18.44 26.62 18.44 1.96 1.16 1.35 1.31
28.18 22.23 28.18 22.12 0.114 0.041 0.058 0.041
0.058 0.041 0.058 0.041 0.09 0.053 0.062 0.053
0.062 0.053 0.062 0.053
*C = c o n v e n t i o n a l analog; A = a d v a n c e d analog; P u b . = p u b l i c ; Pri. = private.
M
Large-scale survey (1 : 2 0 0 0 ) L Planimetry C.Pub. (peri-urban) C.Pri. A.Pub. A.Pri. 31.8 22 31.8 21.9 40 23.7 31.5 26.8
28.4 15.6 28.5 15.6 43.3 15.2 28.1 15.2
43.3 15.6 28 15.6
28 15.6 28 15.6
40.2 23.7 31.6 23.7
32 23.7 31.6 23.7
2 shifts
1 shift
2 shifts
1 shift
1 shift
1 shift
2 shifts
per point surveyed
per dm 2 on map
per point surveyed
per dm 2 on map 2 shifts
Savings o n u n i t e x p e n d i t u r e s (%)
Savings in costs ( U S $ o n u n i t values)
D I G I T A L P L O T T I N G ( f o r a u t o m a t i c c a r t o g r a p h y a n d d a t a files)
No.
Operation
T A B L E 2.2.4.II ( c o n t i n u e d ) c~ b~
53 T A B L E 2.2.4.III S u m m a r y o f f i n a n c i a l savings in a n a l y t i c a l p l o t t i n g t a k e n f r o m T a b l e 2.2.4.II: results d i s t i n g u i s h e d b y t y p e s o f scales, b y sectors, b y c o m p a r i s o n s b e t w e e n t y p e s of analog, b u t with one and two-shift work combined
Savings in analytical over conventional analog
Savings in analytical over advanced analog
Public
Private
Public
Private
+ 16.4% + 36.7%
+ 9.4% + 12.5%
14.8% --- 2.8%
+ 19.4%
+ 29.6%
+ 19.8%
Graphical plotting: Small scale Large scale
+ 33.1% + 37.4%
Digital plotting: Large scale
+ 35.9%
3. S Y N T H E S E S O F C O M P A R I S O N S O F C O S T A N D P R O D U C T I V I T Y S T U D I E S IN C O N V E N T I O N A L A N D A D V A N C E D A N A L O G P H O T O G R A M M E T R Y WITH T H O S E IN A N A L Y T I C A L P H O T O G R A M M E T R Y
3.1. Comparison of time required for identical production 3.1.1. Summary of overall results obtained. Basic gain in time in analytical: (a) for aerotriangulation: 80%; (b) for orientations: 90.5%; and (c) for plotting details: 15%.
3.1.2. First mode of estimating time gained. Let us choose the hypothesis that a single analog instrument is used for aerotriangulation, orientations and detail plotting. Average time gained results from weighting the above percentages because of true statistical productivity (indicated in Tables 2.1.1.). Time gained is thus 22.33%.
3.1.3. Second mode of estimating time gained. In this m o d e it will be assumed that the analog plotter instrument is used only for orienting the stereo pairs and plotting details; aerotriangulation, made on other equipment (stereocomparator or plotter and computer), not being counted. Let us imagine that this analog plotter handles 60 stereo pairs per annum during 1880 working hours (on one shift). This gives 31 h 19 min per pair, 1 h 22 min for orientation and 29 h 57 min for plotting. In this same case, the single analytical stereoplotter will handle the three operations on each pair, i.e.: (a) 0 h 28 min for aerotriangulation; (b) 0 h 08 min for orientation; and (c) and 25 h 27 min for plotting details (85% of 31 h 19 min), i.e. a total of 26 h 03 min per pair. Thus, working 1880 h/yr on one shift, AP's handle more than 72 pairs, an increase in production of 20%.
54
3.1.4. Conclusions concerning time gained. One may accept a gain in time of more t h a n 21% whatever the means compared in analog p h o t o g r a m m e t r y and the scales or t y p e of work under consideration.
3.2. Comparison o f costs for the same work Table 2.2.4 shows t h a t the estimate of financial gain cannot be expressed in an overall manner so simply as productivity because of the great number of parameters. In the case under consideration, however, the direct estimate is defined. Let us simplify several elements in order to facilitate the estimate.
3.2.1. Respective weights o f the 3 phases o f analytical plotting. We find:
(A) Aerotriangulation (on Traster) (B) Orientations (C) Plotting details
1.7914% 0.5118% 97.6968%
Total 100.0000% of analytical expenditures.
3.2.2. Test o f economies achieved in costs. Weighting of operational phases reveals quite evidently t h a t the third phase is determining (Table 2.2.4.I). Whatever attitude is taken, however, with respect to this third phase, one must not lose sight of economies already achieved in the first two recalled below and which are valid for the comparison b o t h with " c o n v e n t i o n a l " analog p h o t o g r a m m e t r y and with " a d v a n c e d " analog p h o t o g r a m m e t r y . In both cases, this comparison is made, on the one hand, for one-shift work and, on the other~ for two-shift work (Table 3.2.2). TABLE 3.2.2 Sum of economies achieved in aerotriangulation and orientation Economies in US$
on one pair on 60 pairs during 5 years
Publicsector
Private sector
1 shift
2 shifts
1 shift
2 shifts
154 9247 46,236
148 8887 44,439
184 11,049 55,248
i63 9790 48,948
Note t h a t even for 60 pairs per year (as we have seen, one may expect to handle 72) during the 5 years of instrument amortization, the gross gain reaches 1/4 of the price o f the analytical plotter (in spite of amortization expenditures), whereas this represents only 2.30% of the instrument's work. This represents an average saving of 85.25% over correlative expenditures in analog p h o t o g r a m m e t r y .
55 For detail surveys, in the "private sector case", we shall consider only twoshifts o f operators, because this is the only practical case in private analytical photogrammetry. The least favorable indication revealed was the comparison with "advanced" analog in small-scale surveys in the private sector, since expenditures are 4.3% greater in analytical (Table 2.2.4.IV). In the latter case, the average weighted with previous phases (Table 3.2.2) leads to a total supplementary expenditure o f 2.24%. We should also point o u t that -- at the same time-- there is still a gain in time of 21%, with a t w o times better accuracy. This is the least favorable case. If the same calculations are made in the most favorable case, the comparison b e t w e e n "conventional" analog and analytical for large-scale survey, public sector, one-shift work, we find an advantage of 34.9% which, considering weighting with the first t w o phases (Table 3.2.2), gives overall savings of 40.45%. All other cases are distributed b e t w e e n these two limits. CONCLUSION OF FINANCIAL STUDY One must emphasise t w o basic points: (1) Amortizations (if applicable: normally for private sector only) have been counted as: (a) 8 years in analog p h o t o g r a m m e t r y with electronic accessories; and (b) 5 years in analytical photogrammetry. Estimates of economies have been minimized in all phases of the study. (2) Systems have been compared within a methodological procedure practiced for analog photogrammetry. This is the case where an analytical instrument is added to other analog instruments in use, b u t without changing the methodology. Since, as is well known, analytical is twice as accurate for the same quality of production, the m e t h o d o l o g y itself must be reconsidered, for example: (a) the scale of the exposures; and the (b) number of geodetic points determined on the terrain, etc. An eclectic adaptation of methods to analytical photogrammetry will give savings quite substantially greater than the " m i n i m u m " estimates indicated above. (3} Besides speed and accuracy (valid in all cases), the basic advantage of analytical plotters is obviously in their use for large-scale surveys and digital photogrammetry. (4) There is no great advantage for the public sector in working two shifts, unless it be to double production. On the other hand, it is advantageous for the private sector, as it is whenever systems based on computers are used. (5) At the present state of the art, there exists no sector in which the use of analytical p h o t o g r a m m e t r y is ill-advised, b u t a study of Table 2.2.3.III covering surveys of details is the determining factor from the financial point of view. Considering the remarkable analytical performance at large scales and in digital surveys, compared with more modest performance at small scales, the
56
question is posed as to whether or not there should be a move to develop analytical second order plotters, in the light of the above study.
REFERENCES Dubuisson, D., 1943a. Sur les applications ~ l'a~rotechnique du redressement des photographics a~riennes. C.R. Acad. Sci., Paris, 216: 867--869. Dubuisson, D., 1943b. Nouvelle m~thode pour la d~termination des ~l~ments de prise d'un clich~ a~rien. C.R. Acad. Sci., Paris, 217: 13--15. Dubuisson, D., 1945. Recherches r~centes sur l'image latente photographique. Publ. Sci. Tech. Minist. Air (Ft.), Notes Tech., No. 17. Dubuisson, D., 1946. D4termination des ~l~ments initiaux d'une photographic a~rienne par le calcul differentiel. L'image latente photographique. Thesei, Facult~ des Sciences de Paris, publ. by Publ. Sci. Tech. Minist. Air (Fr.), No. 202. Dubuisson, D., 1948a. Sur les applications ~ l'a~rotechnique de l'enregistrement photographique de la verticale gyroscopique et de la d~rive. C.R. Acad. Sci., Paris, 276: 309-311. Dubuisson, D., 1948b. Sur une m~thode de transformation des photographies a~riennes inclin~es en rues verticales, present4 par G. Poivilliers. C.R. Acad. Sci., Paris, 276: 309-311. Dubuisson, D., 1950. Restitution planim~trique des photographies a4riennes. Publ. SCi. Tech. Minist. Air (Fr.), Bull. Serv. Tech., No. 113. Dubuisson, D., 1973. Les trente ann~es de la Division des Travaux Topographiques de la Direction de l'Am4nagement Foncier et de l'Urbanisme. Dubuisson, D., 1975. Automatic photogrammetric cartography. Photogramm. Eng. Remote Sensing, 41 (1): 65--74. Dubuisson, D., 1979. Num~risation des images et restitution analytique. Bull. Soc. Fr. Topogr. T~l~detection, pp. 73--74. Dubuisson, D., 1980. La topographie de l'an 2000. XYZ, Rev. Assoc. Ft. Topogr., No. 3. Tarif de l'Etablissement des plans topographiques et parcellaires. Div. Travaux Topogr., Direction Am~nagement Foncier Urbanisme, Minist. Equipement (Fr.) et revisions ult~rieures. Zarzycki, J.M., 1978. An integrated digital mapping system. Can. Surv., 32 (4).
35
COMPARATIVE ECONOMICS AND ANALYTICAL EXPANSION
BERNARD L.Y. DUBUISSON Ecole des Travaux Publics, 20 Avenue Paul Appell, 75014 Paris (France)
(Received August 28, 1980; revised and accepted February 25, 1981)
ABSTRACT Dubuisson, B.L.Y., 1982. Comparative economics and analytical expansion. Photogrammetria, 38: 35--56. This paper presents an economic analysis of the various phases of production, namely: conventional graphic analog photogrammetry, analog photogrammetry equipped with computer-aided peripherals and plotting table, and analytical photogrammetry, together with a comparative synthesis of studies of productivity, accuracy and economics in the various fields. Conclusions are drawn concerning stimulating the development of analytical means for certain economic requirements.
INTRODUCTION Descriptive and q u a n t i t a t i v e m e t r o l o g y is at t h e origin o f all decisions; t h e r e is n o t h i n g n e w in this s t a t e m e n t , f o r " m a s t e r s u r v e y o r s " have always b e e n with us. T o d a y , h o w e v e r , t h e s c o p e o f r e q u i r e m e n t s has b e c o m e m u c h greater, b o t h in t h e spatial a n d m a c r o s c o p i c and m i c r o s c o p i c realms: m a p m a k i n g and cadasters are as m u c h c o n c e r n e d as biological and industrial m e t r o l o g y . This n e w s i t u a t i o n reveals t h e a n a c h r o n o u s precariousness o f t h e means o f m e a s u r e m e n t c o n s i d e r e d u p t o n o w as " c o n v e n t i o n a l " . N e w t e c h n o l o g i c a l d e v e l o p m e n t s have e m e r g e d , h o w e v e r in t o p o g r a p h y and land surveying, b o t h in e l e c t r o - m a g n e t i c distance measuring and in c o m p u t e r based m e t h o d s used f o r o t h e r activities. This e v o l u t i o n was so p r o n o u n c e d t h a t it was believed at o n e t i m e t h a t t h e growing c o n t r o l exercised b y p h o t o g r a m m e r r y o v e r m e a n s o f measuring o n t h e g r o u n d w o u l d b e c o m e less significant. At this p o i n t t h e r e began t h e d e v e l o p m e n t o f analytical p h o t o g r a m m e t r y w h o s e universal a p p l i c a t i o n is t h e o n l y o n e capable o f satisfying o u r n e e d s in t h e m o s t i m p o r t a n t fields w h e r e m o d u l a r i t y , p r o d u c t i v i t y and a c c u r a c y are increasingly d e m a n d e d o f m e a n s o f m e t r o l o g y and are d e t e r m i n i n g f a c t o r s ; f o r e x a m p l e , scientific a n d t e c h n i c a l d e v e l o p m e n t s linked w i t h space research, civil engineering a n d i n d u s t r y . In general, a n d t h r o u g h o u t a l m o s t t h e e n t i r e w o r l d , p h o t o g r a m m e t r i c needs 0031-8663/82/0000--0000/$02.75 © 1982 Elsevier Scientific Publishing Company
36 are satisfied b y " a n a l o g " instruments, but their operating principle leads to all sorts o f limitations which render t h e m inadequate for the fulfillment of numerous present-day requirements, such as the development of automation of measurements which has now become an obvious necessity in all fields. On the other hand, there appears to be no limitation on the use of analytical plotters (AP's) as studied herein with particular attention to the Traster System. Here all simulations, transformations and spatial measurements are mathematical; adaptations to specific production requirements are assured by specific software which may be integrated into the system's overall software in order to solve a given problem. The use of AP's does not really require professional qualifications in photogrammetry and t h e y m a y be quite readily used by the practitioner himself to make his own measurements: the engineer-builder, architect or doctor, for example. Accuracy has been doubled (in the particular case of Traster), while production is improved at a ratio which the present report will define, with correlative influence on savings in production costs. Today, everyone admits t h a t the most productive, accurate and universal application in p h o t o g r a m m e t r y for delicate work can only be analytical, but other factors also become evident: (a) Most photogrammetric work is still involved with mapmaking and cadasters. (b) Practically all photogrammetric instruments in use are analog. They are complemented often by electronic digital acquisition in the model, a function for which t h e y have n o t always initially been designed. They then perform what we shall call -- in this study . . . . conventional" analog photogrammetry. (c) The most recently designed analog instruments facilitate the use of certain a u t o m a t e d functions permitting reducing the importance of labor. However~ t h e y remain limited as to their fields of use and accuracy because of their very principle: in the present study, we shall call their function "advanced" analog p h o t o g r a m m e t r y . Industrialized countries are obliged to gradually renovate that part of their range o f instruments which has become technically outdated. Third World countries must be equipped with new cartographic means in order to acquire cadastral and mapmaking a u t o n o m y , the natural complement of territorial appropriation. (d) The bitterness of competition resulting from the economic situation requires the use of fast, flexible, accurate and economical metrological means, both in cartography and industry. The pragmatism of public officials, however, cannot be satisfied by assertions, however evident t h e y may be. They demand that costs and profits anticipated in such development be calculated so as to make the best adaptation of investments to the case under consideration. The diversity of possible metrological operations does not simplify this sort of economic study, the less so since analytical plotting instruments alone are
37
capable o f performing functions previously performed b y several different, complementary items of equipment; as an example, one might mention the fields of aerotriangulation, graphical and digital plotting, a u t o m a t e d draughting, calculations, etc. As such an economic survey cannot reasonably cover all such work, the present study is confined to a field of photogrammetry in c o m m o n use and where rates are c o m m o n practice: large-scale drawings for development of the French territory. These involve results from photogrammetric surveys made b y a group of agencies over scores of years and gradually brought to their most efficient level of productivity via analog photogrammetry equipped with instruments in current use up to 1975. In order to be exhaustive, however, this study had to be carried further to include the most recent analog instruments, which, through electronic adaptations, improve savings in production costs. Analytical p h o t o g r a m m e t r y will thus be compared successively with: (a) "conventional" analog photogrammetry; and (b) "advanced" analog photogrammetry*. From these two financial and productivity comparisons conclusions will be drawn in which the advantages of the analytical process will be reduced, in principle, to a minimum. In fact, the doubling of analytical accuracy will lead to an evolution of the use m e t h o d o l o g y which will accentuate its productivity, b u t which has not been taken into consideration in this study. 1. P R I N C I P L E S O F THE S T U D Y A N D C O N V E N T I O N A L BASIC E L E M E N T S
1.1. General principles o f the comparative study The basis of the study is the productivity and costs of "conventional" analog photogrammetry the various phases of which are priced at rates which are very well known, and which is carried o u t for public agencies b y established firms. Economies achieved with respect to these rates b y "advanced" analog photogrammetry and b y analytical photogrammetry result from technological advantages and from reduced labor requirements for the t y p e of instrument usually used for a well-defined function. Furthermore, it seemed o p p o r t u n e in the present study to distinguish between the public sector (public cartography and cadaster services etc.) and the private sector (industrial or engineering agencies); the former users invest periodically but do not deduct the annual amortization of their equipment in their public accounting (in general), whereas the private sector, obviously~ is obliged to do so. In the latter case, linearly proportional amortization in time *We shall include in this c a t e g o r y t h e use o f i n s t r u m e n t s f r o m t h e p r e c e d i n g g e n e r a t i o n w h i c h have b e e n e q u i p p e d by t h e i r users w i t h accessories or p e r i p h e r a l s allowing t h e s a m e general uses a n d p e r f o r m a n c e as m o r e r e c e n t analog i n s t r u m e n t s .
38 has been taken into account, but w i t h o u t including interest rates. Finally, estimates have been made on the basis of an annual (conventional) labor period of 1880 working hours covering, on the one hand, one shift per day and~ on the other, two shifts per day. Where cost estimates are required, t h e y have been drawn up in U.S. dollars, w i t h o u t presuming t h a t t h e y apply strictly to the U.S.A. Employees' benefits contributions linked with labor costs, as well as overhead and profits and maintenance, have been estimated in an identical manner for each t y p e o f p h o t o g r a m m e t r y under consideration. These comparisons have also involved amounts devoted to investments (and their amortizations); these latter obviously vary from one country to another because of the diversity of taxes and customs duties, as well as m o n e t a r y fluctuations (comparisons in the present study refer to March, 1979). Since the conclusions will, however, concern only the relationship between costs and productivity of analog plotters and those of analytical (Traster) plotters, results -- as a basis of comparison -- will remain coherent for the various countries, although each elementary value expressed may be contested for a given place or a given circumstance. Because of the multiple nature of the necessary parameters involved this economic study is quite complex; it thus seemed useful to indicate at the beginning the references for tables of results: (2.2.2), (2.2.3), and (2.2.4). We should also mention that, as an item in the final result, the analytical method represents an e c o n o m y of 21% over the analog m e t h o d with tripled accuracy in the large-scale plans studied. These figures, however, will be improved by using an overall methodology adapted to the analytical method.
1.2. Basic price elements for various types of photogrammetry 1.2.1. Hourly labor expenditures for plan-producing agencies (weighted hypothetical values) -- stereoplotter operator: 20.1 US$; draughtsman-assistant: 12.8 US$ -- giving the total labor cost calculated in various cases (see Tables 2.1.2, I, II and III): "1 technician" = 1 plotter only : 20.10 US $ "1.1 technician" = 1 plotter + 1/10th time for 1 assistant: 21.38 US $ "1.5 technician" = 1 plotter + 1/2 time for 1 assistant : 26.50 US $ "2 technicians" = 1 plotter + 1 assistant : 32.90 US $ 1.2. 2. Hourly amortization and main tenance costs (see Table 1.2.2) 1.2.3. Operating costs. Overall costs, unforeseeables, margins or profits are estimated for both public and private sectors at 80% of overall personnel expenditures. 1.2.4. Nature o f expenditures in both private and public sector accounts. We
39
T A B L E 1.2.2. Hourly amortization and maintenance costs Equipment
a Amortization costs
b Maintenance costs
1 2 Presumed 1 2 shift shifts purchase shift shifts price US$ Over 8 years: 5% per year
Type No.
Stereoplotter specification ("advanced" analog)
1
Analog, 2nd order, usable for small scale with digitization and recording
80,000
5.32
2.66
2.13 1.07
2
Analog, 2nd order, usable for small scale with digitization, graphic console of central computer for eventual automatic mapmaking
110,000
7.31
3.66
2.93 1.47
3
Analog, 1st order with co-ordinate recording, tape, semi-automatic table
150,000
9.97
4.99
3.99 2.00
4
Other analog, 1st order with calculation model co-ordinates and tape recording and semi-automatic table, T.V,
202,000
13.43
6.72
5.37 2.69
5
1st order as No. 4 in "digital system", in geographic co-ordinates coded for au~omatic mapmaking
215,000
14.30
7.15
5.72 2.86
Over 5 years: 8% per year 6
AP's: Traster example with table and 64K disc, digital and graphical process in geographic co-ordinates of points
210,000
22.34 11.17
8.94 4.47
assume t h a t t h e cost o f an o p e r a t i o n will be e s t i m a t e d b y a c c o u n t s for t h e following items: (a) f o r p u b l i c s e c t o r : l a b o r (1.2.1); m a i n t e n a n c e (1.2.2.b); o p e r a t i n g costs (1.2.3). (b) f o r private s e c t o r : l a b o r (1.2.1); a m o r t i z a t i o n (1.2.2.a); m a i n t e n a n c e (1.2.2.b); o p e r a t i n g costs (1.2.3). F o r each t y p e o f p r o d u c t i o n , and w h a t e v e r t h e t y p e o f p h o t o g r a m m e t r y involved, e s t i m a t e s will be m a d e f o r o n e shift per d a y , t h e n f o r t w o . In all cases, p r o d u c t i v i t i e s f o r a n a l o g p h o t o g r a m m e t r y will be applied (2.1.1 .II.a, b a n d c). T h e s t u d y will t h e n be c o n t i n u e d f o r a n a l y t i c a l p h o t o g r a m m e t r y using t h e same cases a n d t h e same w o r k i n g p r o c e d u r e , b u t w i t h its o w n p r o d u c t i v i t y .
40
2. ECONOMICANALYSES OF PRODUCTION
2.1. Economic study of analog photogrammetry Two facets will be studied: (a) basic statistical productivity in "traditional" analog photogrammetry which will then be transposed into "advanced analog"; and (b) significant examples from the point of view of productivity and unit prices of cartographic production. These two points will be studied successively in the different versions with respect to: (a) aerotriangulation; (b) model orientation; and (c) detail plotting, small and large scale.
2.1.1. Basic statistical productivity in "conventional" and "advanced" photogrammetry I. Aerotriangulation. All operations included: 2 h 50 min per stereo pair, i.e., 2.8 pairs per 8-hour day.
H. Plotting. Graphical and digital. These productivity values are not scores achieved over short periods of time, but are taken from statistical results of bid proposals filed by highly-qualified
TABLE 2.1.1.II a. T i m e r e q u i r e d f o r f o r m a t i o n a n d o r i e n t a t i o n m o d e l Formation and numerical orientation model Setting again a model Format, ion and graphical orientation model .................................................................................
1 h 20 rain 40 rain 2 h 5 rain
Average duration
1 h 22 rain
Scale
Planimetry of density of residential urban suburb Rate per dm 2
Rate per stereopair
Altimetry: mountain,
Rate for 1 point
Rate per linear (din) of contour
1 1 . 3 3 sec
10.8 rain
11.5
10.8 min
average slopes 15%
Rate per dm 2
Rate per stereopair
b. C o m p i l a t i o n t i m e in g r a p h i c a l p l o t t i n g Plan 1 : 2000 Photo 1:8000
1 h 23 rain
Map 1 : 25,000
3 h
5 rain
27 h 4 0 rain
7 h 35 rain
c. T i m e r e q u i r e d f o r d i g i t a l p l o t t i n g p e r f o r m e d Plan 1 : 2000 Photo 1 : 8000
1 h 45 rain
34 h 10 rain
sec
for automated
2 h 40 rain
18h
54 h
44h
draughting and creating data storage files
1 3 . 9 7 sec a
aIncluding conventional point-coding time. bAltimetry defined by interpolations of altimetric points or by D T M
5.08 rain b
profiles.
6 h 46 rain b
41
agencies in response to calls for bids for large projects. Obviously, they include normal coverage for risks involved in technological production with its monitoring and corrections. These estimates result from 15 years of production; average j o b size was 25 stereo models for each job, with 300 jobs per year. Modifications achieved via "advanced" stereoplotters have not been counted in productivity b u t only in unit prices for certain production operations; these costs are sometimes reduced because of the decrease in the number of technicians assigned (statistically) to each instrument. This factor will appear in the study of "significant examples".
2.1.2. Significant examples of productivity and costs for a stereo pair in analog photogrammetry (see Table 2.1.2) 2.2. Economic study o f analytical photogrammetry 2.2.1. Conventional bases for estimates Although the study of the yield of analog plotters could be based on longestablished practices, this is evidently not the case with analytical plotters; Traster, in particular, on which this analysis is based, has not been in use for long nor used regularly in intensive mapmaking production which can be statistically equivalent to that of analog instruments. In an initial phase, and on the basis of acquired experience, one must, therefore, be content with evaluating the logical increase in productivity obtained in the various operating phases of analytical practice. Special attention will be given to aerotriangulation aspects as well as model formation and orientation, which can be most readily estimated. Most of all, however, attention will be focussed on the general conditions for measuring detailed surveys on the instrument. Economies achieved will thus be analyzed successively in: (a) aerotriangulation; (b) model formation and orientation; and (c) operations involving plotting of small- and large~cale details for b o t h 1 and 2 shifts per day. One can accept, arbitrarily and for the needs of a rough evaluation of some estimates, that a single analytical stereoplotter performs all the photogrammetric operations needed for 60 stereo pairs during the 1880 annual working hours o f one work shift. In the case of Traster, all operations are performed b y a single technician, the plotter. It is therefore interesting to recall the estimates made in § 1.2.1. to 1.2.4. above, dealing with various costs constituting overall production expenditures. For an AP such as Traster, we have, in US dollars:
Aerotriangulation
Nature
3
Equipmerit type number (see 1.2.2.)
2 h 50 m i n
Duration of operation
Formation model a n d graphical orientation
D
Small scale, average costs:
1
Settingagain a model
C
1
1
Formation model and numerical orientation
B
Small scale survey, 1 : 25, 000
2 h 05 m i n
40 min
1 h 20 m i n
II. M o d e l - - Relative a n d a b s o l u t e o r i e n t a t i o n
A
I.
No.
Operation
C.Pub. A.Pub. C.Pri. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
"Con." "Adv." Publ. Pri.l
1.5 1.5 1.5 1.5
1.5 1.5 1.5 1.5
1.5 1.5 1.5 1.5
1
No. o f technicians
48.77 51.43 48.77 51.43 48.77 51.43 48.77 51.43
49.83 55.15 49.83 55.15
48.77 51.43 48.77 51.43
38.18 43.17 38.18 43.17
2 shifts
49.83 55.15 49.83 55.15
49.83 55.15 49.83 55.15
40.17 50.14 40.17 50.14
1 shift
C o s t s per hour
67.82 67.82 75.07 75.07
103.81 114.90 103.81 114.90
33.22 36.77 33.22 36.77
66.44 73.53 66.44 73.53
113.81 142.06 112.81 142.06
1 shift
66.38 66.38 70.00 70.00
101.60 107.15 101.60 107.15
32.51 34.29 32.51 34.29
65.03 68.57 65.03 68.57
108.18 122.31 108.18 122.31
2 shifts
Co~t~ production
T A B L E 2.1.2. Significant examples o f productivity and costs for a stereopair in analog p h o t o g r a m m e t r y
b~
NaCre
Setting again a model
Formation model and graphical orientation
F
G
3
3
3
Equipment type number (see 1.2.2.)
2 h 05 rain
40 min
1 h 20 rain
Duration of operation
1.5 1.5 1.5 1.5 1.5 1,5 1.5 1.5
C.Pub. C.Pri, A.Pub. A.Pri. C.Pub. C.Pri. A.Pub. A.Pri. C.Pub. A.Pub. C.Pri. A.Pri.
1.5 1.5 1.5 1.5
No, of technicians
C.Pub. C.Pri. A.Pub. A.Pri.
"Con." "Adv." Fubt. Pri.l
51.69 61.66 51.69 61.66
51.69 61.66 51.69 61.66
51.69 61.66 51,69 61.66
1 shift
49.70 54.69 49.70 54.69
49.70 54.69 49.70 54,69
49.70 54.69 49.70 54.69
2 shifts
Costs per hour
70.36 70.36 83.93 83,93
107.69 128.46 107.69 128.46
34.46 41.11 34.46 41.11
68.92 82.21 68,92 82.21
1 shift
67.65 67.65 74.44 74.44
103.54 113.94 103.54 113.94
33.13 36.46 33.13 36.46
66.27 72.92 66.27 72.92
2 shifts
Costs production
1 Abbreviations in this and following tables signify: C. = " c o n v e n t i o n a l " analog p h o t o g r a m m e t r y ; A. = " a d v a n c e d " analog photogrammetry; Pub. = public sector; Pri, = private sector.
costs:
Large scale, average
Formation model and numerical orientation
E
Large scale survey, 1 : 2 0 0 0
No.
Operation
TABLE 2.1.2. (continued)
2.1.2. (continued)
Nature
Equipment type number
Duration of operation per d m 2 a n d per survey p o i n t
1
1
Planimetry (peri-urban)
Altimetry (mountain)
Planimetry (peri-urban)
Altimetry (mountain)
J
K
3
3
Large-scale survey (1 : 2000)
H
Small-scale survey (1 : 25,000)
2 h 40 m i n / d m :
11.33 s e c / p o i n t
1 h 23 m i n / d m :
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A.Pri. 1.5 1.5 1.1 1.1
2 2 1.1 1.1
1.5 1.5 1.1 1.1
C.Pub. C.Pri. A.Pub. A.Pri.
18 h / d m 2
No. technicians employed
2 2 1.1 1.1
C.Pub. C.Pri. A.Pub. A.Pri.
3 h 05 m i n / d m 2 C.Pub. C.Pri. 11.5 s e c / p o i n t A.Pub. A.Pri.
G R A P H I C A L P L O T T I N G (see Table 2.1.1.IIb)
No.
Operation
III. P l o t t i n g details in analog p h o t o g r a m m e t r y
TABLE
61.22 66.21 40.48 45.47 49.70 54.69 40.48 45.47
51.69 61.56 42.47 52.44
48.77 51.43 39.55 42.21
49.83 55.15 40.61 45.93
63.27 73.38 42.47 52.44
53.29 62.95 39.55 42.21
2 shifts
61.35 66.77 40.61 45.93
1 shift
Costs p e r hour
137.84 164.43 113.25 139.84
87.52 101.23 58.75 72.54
896.94 992.70 730.98 826.74
189.16 205.57 125.21 141.62
1 shift
132.53 145.84 107.95 121.25
84.69 91.59 56.00 62.90
877.86 925.74 711.90 759.78
164.31 194.10 121.95 130.15
2 shifts
per d m ~ o n m a p
-----
0.199 0.24 0.136 0.165
-...... ---
0.196 0.213 0.13 0.147
1 shift
0.193 0.208 0.127 0.143
0.17 0.201 0.126 0.135
2 shifts
per p o i n t s u r v e y e d
P r o d u c t i o n costs, u n i t costs c o u n t e d
Nature
Equipment type number
Duration of operation per dm 2 and per survey point
No. technicians employed
C.Pub. C.Pri. A.Pub. A.Pri.
L
5
5
Planimetry (peri-urban)
Altimetry (mountain) DTM; supplementary points
Large-scale survey (1 : 2000) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5
1 h 45 m i n / d m 2 C.Pub. C.Pri. 13.9 sec/point A.Pub. A.Pri. 5 min 18 sec/dm 2C.Pub. C.Pri. 13.9 sec/point A.Pub. A.Pri.
DIGITAL PLOTTING (for automatic cartography) (see Table 2.1.1.Iic)
No.
Operation
T A B L E 2.1.2. (continued)
50.56 57.77 50.56 57.77 50.56 57.77 50.56 57.77
53.42 67.72 53.42 67.72
2 shifts
53.42 67.72 53.42 67.72
1 shift
hour
Costs per
4.52 5.73 4.52 5.73
93.48 118.51 93.55 118.51
1 shift
4.28 4.89 4.28 4.89
88.48 101.10 88.48 100.99
2 shifts
per dm 2 on map
0.207 0.263 0.207 0.263
0.207 0.263 0.207 0.263
1 shift
0.196 0.224 0.196 0.224
0.196 0.224 0.196 0.224
2 shifts
per point surveyed
Production costs, unit costs counted
46 TABLE 2.2.1. Overall costs of hourly production
One-shift operation Two-shift operation
Public sector
Private sector
45.12 40.65
67.46 51.82
2. 2.2. Aerotriangulation Judiciously adapted to the various operational phases of aerotriangulation, analytical plotting permits of considerable simplification of previous routines imposed b y conventional methods. It is not o p p o r t u n e to give details of this procedure here, although several aspects may be mentioned: (1) Following a computer-slaved order to shift the exposures, possibility of: (a) automatic plotting on the image of a transfer point already used on the stereo-pairs and sometimes contiguous strips, with help of slaved electronic removal system; (b) definitive formation of models during the acquisition phase in the real-time strip aerotriangulation. (2) Thanks to the automatic servo-travel, checking coherence and accuracy of transfer points used on a model before any insertion into aerotriangulation calculations. (3) Possibility of real-time sequential calculation of aerotriangulation for each strip as acquisitions progress. (4) Possibility of ensuring definitive correction in a few minutes of the block of strips on the computer (Traster computer) in semi-deferred time. Finally, m e m o r y storage of definitive results: transfer point numbers, exposure co-ordinates, corrected space co-ordinates, and m e m o r y storage of parameters of the various orientations (internal, relative, absolute) for each stereo pair. All these possibilities eliminate the long and delicate organizing work preceding measurements, with the familiar accessories for pin-pointing and transferring points. The work involved in final storage of results in archives also becomes unnecessary. The reliability of such results is optimal, because each detail operation is checked in real time, thus permitting, if necessary, immediate touching-up. It is thus quite evident that productivity is considerably increased since the time gained is estimated at 80% with respect to previous methods. In the various cases considered, it is advisable to calculate anticipated savings in aerotriangulation on an analytical plotter (Traster, for example); it should be done for one pair, 60 pairs (which, hypothetically, can be completely processed annually b y a single instrument) and, finally, for a period of five years {within the same hypothesis).
47 TABLE 2.2.2 Savings (in US dollars)
Savings achieved on one stereo pair Savings achieved on 60 stereo pairs Savings achieved over 5 years
Case of a public service
Case of a private agency
1 shift per day
2 shifts per day
I shift per day
2 shifts per day
91.05 5,463.60 27,315.00
86.54 5,192.40 25,962.00
113.65 6,819.00 34,095.00
97.85 5,871.00 29,355.00
2. 2.3. Formation and orientation models A trained operator takes 10 rain to carry out a complete setting up operation for a stereo pair; this value must be compared with the average time spent in analog procedure, i.e. 82 min (Table 2.1.1. II). In addition, when orientation has been set previously during aerotriangulation, it is indispensable to set one of the pairs anew on AP's (Traster, for example) in order to exploit details of plotting; this "partial orientation" requires only 4 minutes per stereo pair, whereas 40 rain are required in analog p h o t o g r a m m e t r y for a similar case of setting up a model again. In fact, all aerotriangulation parameters are stored in the m e m o r y and it suffices to extract them. To obtain a simple overall comparison permitting of expressing sums economized on analytical orientations, we shall use the hypothesis of equal distribution of the various types of work previously considered under the heading "small-scale surveys" on the one hand, and "large scale surveys" on the other. (See Table 2.1.2. II, operations B, C and D for small scales, and operations E, F and G for large scales.) In Table 2.2.3, the average cost is shown of orientation of a pair in analog procedure, t h a t in analytical procedure and the savings achieved thanks to the latter for the eight usual cases for such estimates: public sector, private sector, one-shift and two-shift daily work, and finally, small and large scale. 2.2.4. Plotting details AP's have been designed to be used by a single technician, the plotter. He can intervene manually on the co-ordinatograph
5.42
6.02
74.44
67.65
83.93 for o n e pair f o r 60 p a i r s ] y e a r over 5 years
b C
8.99
a
Average overall savings o n o r i e n t a t i o n s c o m e t o 90.5%.
Averages, all scales c o m b i n e d :
70.36
Large-scale survey
8.99
5.42
6.02
66.38
75.07
70.00
67.82
2 shifts
1 shift
2 shifts
1 shift
1 shift
Small-scale survey
1 shift
Publ. s e c t o r
Priv. s e c t o r
Publ. s e c t o r
18,477
18,921
61.59
63.07
6.91
3695
62.23
3784
60.96 64.34
21,153
4230
70.51
74.94
66.08
1 shift
1 shift 61.80
Priv. s e c t o r
Publ. s e c t o r 2 shifts
Savings a c h i e v e d f o r o r i e n t a t i o n o f 1 stereo-pair
6.91
2 shifts
Priv. s e c t o r
Analytical
Analog
2 shifts
Cost of orientation for 1 stereo-pair
Avg. cost of o r i e n t a t i o n for 1 stereo-pair
Average savings a c h i e v e d in o r i e n t a t i o n s ( e x p r e s s e d in US dollars)
T A B L E 2.2.3
19,593
3919
65.31
57.53
63.09
2 shifts
QO
49
Another favorable element lies in the grouping of all controls, thus sparing the operator the need for moving about: these are keys on the control desk, the t u b e for dialogue with the computer, the TV tube and means for removal through the model. Yet another favorable factor is the replacement of the traditional hand cranks for X and Y travel b y a ball moving on an air cushion; after a brief period of adjustment, the operator usually agrees that this latter is better adapted to h u m a n physiology. In this case, Z travel is controlled b y the operator's other hand, rotating a small cylinder and advantageously replacing the customary circular pedal. Since statistics have n o t yet been established for very long operating periods~ one must be content with logical -- slightly subjective -- evaluation in order to estimate productivity gains achieved. One may thus estimate that, under equivalent production conditions, the described features increase productivity in a proportion which might be reckoned very prudently at a minimum of 15% on the best "advanced" analog plotting instrument. The following tables deal with a survey of details using an AP. Table 2.2.4.I gives the cost in US dollars for operations previously dealt with in analog photogrammetry (in 2.1.2.III). Table 2.2.4.II gives savings achieved with respect to conventional and advanced analog procedure. Tables 2.2.4.III and 2.2.4.IV are summaries extracted from the preceding data, enabling analysis of the results.
T A B L E 2.2.4.IV A n o t h e r a s p e c t of f i n a n c i a l savings Averages s u m m e d u p f r o m T a b l e 2.2.4.II as a b o v e b u t w i t h sole r e f e r e n c e t o w o r k in t w o shifts.
conventional analog
Savings in a n a l y t i c a l over advanced analog
Public
Private
Public
Private
+ 24.8% + 38.5%
+ 12.7% + 14.7%
-4.3% + 3.3%
+ 23.3%
+ 31.6%
+ 2.4%
Savings in a n a l y t i c a l o v e r
Graphical plotting: Small scale Large scale
+ 33.4% + 39.4%
Digital plotting: Large scale
+ 36%
I t s h o u l d b e stressed that comparisons herein are m a d e o f costs u n d e r h y p o t h e s e s d e f i n e d a b o v e , b u t in all cases o f detail plotting: (1) s p e e d is g r e a t e r b y 12% in a n a l y t i c a l ; (2) a c c u r a c y is t r i p l e d ; a n d (3) t h r o u g h o u t t h e w o r l d , the normal working day on c o m p u t e r e q u i p m e n t is t w o shifts (i.e. t h e final f i n a n c i a l r e s u l t in the t a b l e above).
Nature
Number type equipment AP's
Duration of o p e r a t i o n for 1 d m 2 and 1 1 point surveyed
Public sector Private sector
No. of technicians 1 shift
Cost per hour
2 shifts
Altimetry (mountain)
I
6
6
Altimetry (mountain)
K
6
6
2 h 16 m i n / d m 2
1 h 10 m i n / d m 2 9.63 s e c / p o i n t
15 h 18 m i n / d m 2
2 h 37 m i n / d m 2 9.77 s e c / p o i n t
Pub. Pri.
Pub. Pri.
Pub. Pri.
Pub. Pri.
1 1
1 1
1 1
1 1
45.12 67.46
45.12 67.46
45.12 67.46
45.12 67.46
40.65 51.82
40.65 51.82
40.65 51.82
40.65 51.82
102.27 152.91
52.64 78.70
690.34 1034.14
118.06 176.52
1 shift
92.14 117.46
47.42 60.46
621.95 792.85
106.37 135.60
2 shifts
dm: on map
. . . . --
0.121 0.]8
---
0.122 0.183
1 shift
L
Altimetry (mountain) supplementary p o i n t s DTM
Planimetry (peri-urban)
6
Large-scale survey (1 : 2000)
4 min 32 s e c / d m 2 11.87 s e c / p o i n t
1 h 29 r a i n / d i n 2 11.87 s e c / p o i n t Pub. Pri.
Pub. Pri.
1 1
1 1
40.65 51.82 40.65 51.82
45.12 67.46 45.12 67.46
3.25 4.86
66.93 100.07
2.93 3.73
60.30 78.87
0.149 0.222
0.149 0.222
0.134 0.171
0.134 0.171
0.109 0.139
---
0.11 0.141
2 shifts
point surveyed
P r o d u c t i o n costs: u n i t costs for: u n i t c o s t s for:
2. D I G I T A L P L O T T I N G c o d e d for a u t o m a t i c c a r t o g r a p h y ( p r o d u c t i v i t y values f r o m Table 2.1.1.Iic increased by 15%)
Planimetry (peri-urban)
J
Large-scale survey (1:2000)
Planimetry (peri-urban)
H
Small-scale survey (1:25,000)
1. G R A P H I C A L P L O T T I N G ( p r o d u c t i v i t y values f r o m Table 2.1.2.b increased b y 15%
No.
Operation
Plotting details in analytical p h o t o g r a m m e t r y
T A B L E 2.2.4.I
¢51 O
Nature
C.Pub. C.Pri. A,Pub. A,Pri.*
Altimetry (mountain)
I
C.Pub. C.Pri. A.Pub. A.Pri.
C.Pub. C.Pri. A.Pub. A,Pri.
Planimetry (peri-urban)
Altimetry (mountain)
J
K
C.Pub. C.Pri. A.Pub. A,Pri.
C.Pub. C.Pri. A.Pub. A.Pri.
Large-scale survey (1 : 2000)
Planimetry (peri-urban)
H
Small-scale survey (1:25,000)
GRAPHICAL PLOTTING
No.
Operation
35.57 11.52 10.98 13.07
34.88 48,59 6.11 --6.16
206.60 -39.44 40,64 -205.40
71.10 29.05 7.15 --37.90
40.39 28.38 15.81 3.79
37.47 44.37 8.58 2.44
255.90 132.89 89.95 -33.07
57.94 58.50 15.58 -- 5 . 4 5
0.078 0.119 0.015 --0.015
--
- -
---
0.074 0.03 0.008 --0.036
2
4
.
8
4
- - 9 . 3
4
30.5
3 . 1
14.6 --
.
44.2 48.4 15.3 3.9
-
9.7
-
- -
0
19.5
25.8
39.9 48 10.4 --8.5
-
0
29.20 14.40 12.60
35.3 30.1 12.8 --4.2
2 shifts
7
0.084 0.099 0.018 0.004
-
23.00 --4.00 5.50
37.6 14.1 5.7 --26.6
1 shift
--
•- -
- -
---
- -
0.06 0.06 0.016 --0.006
2 shifts
1 shift
1 shift
2 shifts
per d m 2 o n m a p
per point surveyed
per d m 2 on m a p
- -
- -
--
- -
- -
--
- -
43.5 47.6 14.2 2.8
--
---
--
35.3 29.9 12.7 --4.4
2 shifts
(continued)
40.4 49.6 11 --9 --
- -
----
37.9 14.1 6.2 --24.5
1 shift
per point surveyed
S a v i n g s o n u n i t e x p e n d i t u r e s (%)
Savings in c o s t s ( U S $ o n u n i t v a l u e s )
Savings a c h i e v e d via a n a l y t i c a l over " c o n v e n t i o n a l " a n d " a d v a n c e d " a n a l o g ( w i t h t r i p l e d a c c u r a c y a n d s a m e m e t h o d o l o g y )
T A B L E 2.2.4.II
Oa
Nature
C.Pub. C.Pri. A.Pub. A.Pri.
Altimetry (mountain) supplementary p o i n t s DTM
C.Pub. C.Pri. A.Pub. A.Pri.
2.48 0.87 1.27 0.87
26.55 18.44 26.62 18.44 1.96 1.16 1.35 1.31
28.18 22.23 28.18 22.12 0.114 0.041 0.058 0.041
0.058 0.041 0.058 0.041 0.09 0.053 0.062 0.053
0.062 0.053 0.062 0.053
*C = c o n v e n t i o n a l analog; A = a d v a n c e d analog; P u b . = p u b l i c ; Pri. = private.
M
Large-scale survey (1 : 2 0 0 0 ) L Planimetry C.Pub. (peri-urban) C.Pri. A.Pub. A.Pri. 31.8 22 31.8 21.9 40 23.7 31.5 26.8
28.4 15.6 28.5 15.6 43.3 15.2 28.1 15.2
43.3 15.6 28 15.6
28 15.6 28 15.6
40.2 23.7 31.6 23.7
32 23.7 31.6 23.7
2 shifts
1 shift
2 shifts
1 shift
1 shift
1 shift
2 shifts
per point surveyed
per dm 2 on map
per point surveyed
per dm 2 on map 2 shifts
Savings o n u n i t e x p e n d i t u r e s (%)
Savings in costs ( U S $ o n u n i t values)
D I G I T A L P L O T T I N G ( f o r a u t o m a t i c c a r t o g r a p h y a n d d a t a files)
No.
Operation
T A B L E 2.2.4.II ( c o n t i n u e d ) c~ b~
53 T A B L E 2.2.4.III S u m m a r y o f f i n a n c i a l savings in a n a l y t i c a l p l o t t i n g t a k e n f r o m T a b l e 2.2.4.II: results d i s t i n g u i s h e d b y t y p e s o f scales, b y sectors, b y c o m p a r i s o n s b e t w e e n t y p e s of analog, b u t with one and two-shift work combined
Savings in analytical over conventional analog
Savings in analytical over advanced analog
Public
Private
Public
Private
+ 16.4% + 36.7%
+ 9.4% + 12.5%
14.8% --- 2.8%
+ 19.4%
+ 29.6%
+ 19.8%
Graphical plotting: Small scale Large scale
+ 33.1% + 37.4%
Digital plotting: Large scale
+ 35.9%
3. S Y N T H E S E S O F C O M P A R I S O N S O F C O S T A N D P R O D U C T I V I T Y S T U D I E S IN C O N V E N T I O N A L A N D A D V A N C E D A N A L O G P H O T O G R A M M E T R Y WITH T H O S E IN A N A L Y T I C A L P H O T O G R A M M E T R Y
3.1. Comparison of time required for identical production 3.1.1. Summary of overall results obtained. Basic gain in time in analytical: (a) for aerotriangulation: 80%; (b) for orientations: 90.5%; and (c) for plotting details: 15%.
3.1.2. First mode of estimating time gained. Let us choose the hypothesis that a single analog instrument is used for aerotriangulation, orientations and detail plotting. Average time gained results from weighting the above percentages because of true statistical productivity (indicated in Tables 2.1.1.). Time gained is thus 22.33%.
3.1.3. Second mode of estimating time gained. In this m o d e it will be assumed that the analog plotter instrument is used only for orienting the stereo pairs and plotting details; aerotriangulation, made on other equipment (stereocomparator or plotter and computer), not being counted. Let us imagine that this analog plotter handles 60 stereo pairs per annum during 1880 working hours (on one shift). This gives 31 h 19 min per pair, 1 h 22 min for orientation and 29 h 57 min for plotting. In this same case, the single analytical stereoplotter will handle the three operations on each pair, i.e.: (a) 0 h 28 min for aerotriangulation; (b) 0 h 08 min for orientation; and (c) and 25 h 27 min for plotting details (85% of 31 h 19 min), i.e. a total of 26 h 03 min per pair. Thus, working 1880 h/yr on one shift, AP's handle more than 72 pairs, an increase in production of 20%.
54
3.1.4. Conclusions concerning time gained. One may accept a gain in time of more t h a n 21% whatever the means compared in analog p h o t o g r a m m e t r y and the scales or t y p e of work under consideration.
3.2. Comparison o f costs for the same work Table 2.2.4 shows t h a t the estimate of financial gain cannot be expressed in an overall manner so simply as productivity because of the great number of parameters. In the case under consideration, however, the direct estimate is defined. Let us simplify several elements in order to facilitate the estimate.
3.2.1. Respective weights o f the 3 phases o f analytical plotting. We find:
(A) Aerotriangulation (on Traster) (B) Orientations (C) Plotting details
1.7914% 0.5118% 97.6968%
Total 100.0000% of analytical expenditures.
3.2.2. Test o f economies achieved in costs. Weighting of operational phases reveals quite evidently t h a t the third phase is determining (Table 2.2.4.I). Whatever attitude is taken, however, with respect to this third phase, one must not lose sight of economies already achieved in the first two recalled below and which are valid for the comparison b o t h with " c o n v e n t i o n a l " analog p h o t o g r a m m e t r y and with " a d v a n c e d " analog p h o t o g r a m m e t r y . In both cases, this comparison is made, on the one hand, for one-shift work and, on the other~ for two-shift work (Table 3.2.2). TABLE 3.2.2 Sum of economies achieved in aerotriangulation and orientation Economies in US$
on one pair on 60 pairs during 5 years
Publicsector
Private sector
1 shift
2 shifts
1 shift
2 shifts
154 9247 46,236
148 8887 44,439
184 11,049 55,248
i63 9790 48,948
Note t h a t even for 60 pairs per year (as we have seen, one may expect to handle 72) during the 5 years of instrument amortization, the gross gain reaches 1/4 of the price o f the analytical plotter (in spite of amortization expenditures), whereas this represents only 2.30% of the instrument's work. This represents an average saving of 85.25% over correlative expenditures in analog p h o t o g r a m m e t r y .
55 For detail surveys, in the "private sector case", we shall consider only twoshifts o f operators, because this is the only practical case in private analytical photogrammetry. The least favorable indication revealed was the comparison with "advanced" analog in small-scale surveys in the private sector, since expenditures are 4.3% greater in analytical (Table 2.2.4.IV). In the latter case, the average weighted with previous phases (Table 3.2.2) leads to a total supplementary expenditure o f 2.24%. We should also point o u t that -- at the same time-- there is still a gain in time of 21%, with a t w o times better accuracy. This is the least favorable case. If the same calculations are made in the most favorable case, the comparison b e t w e e n "conventional" analog and analytical for large-scale survey, public sector, one-shift work, we find an advantage of 34.9% which, considering weighting with the first t w o phases (Table 3.2.2), gives overall savings of 40.45%. All other cases are distributed b e t w e e n these two limits. CONCLUSION OF FINANCIAL STUDY One must emphasise t w o basic points: (1) Amortizations (if applicable: normally for private sector only) have been counted as: (a) 8 years in analog p h o t o g r a m m e t r y with electronic accessories; and (b) 5 years in analytical photogrammetry. Estimates of economies have been minimized in all phases of the study. (2) Systems have been compared within a methodological procedure practiced for analog photogrammetry. This is the case where an analytical instrument is added to other analog instruments in use, b u t without changing the methodology. Since, as is well known, analytical is twice as accurate for the same quality of production, the m e t h o d o l o g y itself must be reconsidered, for example: (a) the scale of the exposures; and the (b) number of geodetic points determined on the terrain, etc. An eclectic adaptation of methods to analytical photogrammetry will give savings quite substantially greater than the " m i n i m u m " estimates indicated above. (3} Besides speed and accuracy (valid in all cases), the basic advantage of analytical plotters is obviously in their use for large-scale surveys and digital photogrammetry. (4) There is no great advantage for the public sector in working two shifts, unless it be to double production. On the other hand, it is advantageous for the private sector, as it is whenever systems based on computers are used. (5) At the present state of the art, there exists no sector in which the use of analytical p h o t o g r a m m e t r y is ill-advised, b u t a study of Table 2.2.3.III covering surveys of details is the determining factor from the financial point of view. Considering the remarkable analytical performance at large scales and in digital surveys, compared with more modest performance at small scales, the
56
question is posed as to whether or not there should be a move to develop analytical second order plotters, in the light of the above study.
REFERENCES Dubuisson, D., 1943a. Sur les applications ~ l'a~rotechnique du redressement des photographics a~riennes. C.R. Acad. Sci., Paris, 216: 867--869. Dubuisson, D., 1943b. Nouvelle m~thode pour la d~termination des ~l~ments de prise d'un clich~ a~rien. C.R. Acad. Sci., Paris, 217: 13--15. Dubuisson, D., 1945. Recherches r~centes sur l'image latente photographique. Publ. Sci. Tech. Minist. Air (Ft.), Notes Tech., No. 17. Dubuisson, D., 1946. D4termination des ~l~ments initiaux d'une photographic a~rienne par le calcul differentiel. L'image latente photographique. Thesei, Facult~ des Sciences de Paris, publ. by Publ. Sci. Tech. Minist. Air (Fr.), No. 202. Dubuisson, D., 1948a. Sur les applications ~ l'a~rotechnique de l'enregistrement photographique de la verticale gyroscopique et de la d~rive. C.R. Acad. Sci., Paris, 276: 309-311. Dubuisson, D., 1948b. Sur une m~thode de transformation des photographies a~riennes inclin~es en rues verticales, present4 par G. Poivilliers. C.R. Acad. Sci., Paris, 276: 309-311. Dubuisson, D., 1950. Restitution planim~trique des photographies a4riennes. Publ. SCi. Tech. Minist. Air (Fr.), Bull. Serv. Tech., No. 113. Dubuisson, D., 1973. Les trente ann~es de la Division des Travaux Topographiques de la Direction de l'Am4nagement Foncier et de l'Urbanisme. Dubuisson, D., 1975. Automatic photogrammetric cartography. Photogramm. Eng. Remote Sensing, 41 (1): 65--74. Dubuisson, D., 1979. Num~risation des images et restitution analytique. Bull. Soc. Fr. Topogr. T~l~detection, pp. 73--74. Dubuisson, D., 1980. La topographie de l'an 2000. XYZ, Rev. Assoc. Ft. Topogr., No. 3. Tarif de l'Etablissement des plans topographiques et parcellaires. Div. Travaux Topogr., Direction Am~nagement Foncier Urbanisme, Minist. Equipement (Fr.) et revisions ult~rieures. Zarzycki, J.M., 1978. An integrated digital mapping system. Can. Surv., 32 (4).