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Transportation and global climate change
Book reviews
developed by illustrating the transferability of pollutants from one medium to another. The second part of the book is concerned with the human health effects of pollutants. The chronological reader is led easily from passages in preceding chapters that are concerned with indoor air pollution and respiratory effects of air pollution into subsequent chapters that deal with a more detailed examination of human health toxicology. Neurotoxicity, carcinogenesis developmental and genetic toxicology are all described taking as a starting point first principles and are developed in enough detail in order that the reader appreciates the particular role played by environmental pollutants in each case. The overview is completed with separate chapters on social issues such as risk assessment and environmental economics and the role of environmental toxicology in regulation and policy considerations. Although this book is not unique in setting itself the task of providing an overview of environmental toxicology, what sets it apart rom existing texts is its accessibility. This is partly accomplished by the clear manner in which it has been written making use of over 100 tables and illustrations. Most helpful though is the liberal use of case studies that are used to illustrate the themes of each chapter. These range from those commonly used to exemplify themes in environmental science such as the case of DDT and PCBs, to lesser known examples illustrating specific problems. What I found most fascinating and particularly instructive in these was their historical dimension, which is frequently omitted when referring to cas cdlibre. Conversely, the book has clearly been written with a North American reader in mind with little reference being made to European or Asian examples of pollution, of which there are many possible to choose from. Overall though this work will, I believe, achieve its aspirations of being a standard introductory text to the field, particularly in the US.
Environmental
Steve Ho//ins Consultant London UK
THE GLOBAL CASINO. AN INTRODUCTION TO ENVIRONMENTAL ISSUES by N Middleton Edward Arnold, London, 1995, 332pp, f15.99 paperback
cial on the human side. The chapter on soil erosion, for example, notes that the driving forces in erosion and conservation are economic, social and political but the chapter gives more detail about the physical processes that the social processes - but at least the social processes are acknowledged and stressed.
ISBN o-340-59493-4
The implications of the title are that ‘environmental issues involve winners and losers’ with the analogy that ‘the casino’s chance elements and the players’ imperfect knowledge of the outcomes of their actions are relevant in that our understanding of how the Earth works is far from perfect’ and also ‘some players can afford to take part.. while others are less able’. An important aspect of the book is ‘its illustration of success as well as ‘horror’ stories’. After the two introductory chapters on the physical and human environment, the book covers deforestation, desertification, food production, soil erosion, threatened species, climatic change, acid rain, oceans, coastal problems, rivers, lakes and wetlands, big dams, urban environments, transenergy waste management, port, production, mining, war and natural hazards, ending with a consideration of conservation and sustainable development. The book is extremely sound, rather than innovative or ground-breaking in its approach, and covers basic theory, examples and illustrations, with a profusion of photographs and diagrams which makes the subject live. The volume should find a ready home in the sixth form and early undergraduate years alike. The real strength lies in the fact that the book outlines both the workings of the physical environment and the political, economic and social frameworks in which the issues occur. This immediately lays the book open to the possibility that it can be criticized for being superficial or naive on either the physical or the human side, but I think that, in fact, the book manages to achieve a very reasonable balance between the two aspects, though perhaps tending towards being superti-
Stephen Trudgill Reader in Geography University of Sheffield, UK
TRANSPORTATION AND GLOBAL CLIMATE CHANGE edited by David L Greene and Danilo J Santini American Council Efficient Economy, 1993, tJS$28.00
for an EnergyWashington, DC,
ISBN O-918249-17-1
‘In matters of grave importance, style, not sincerity is the vital thing’, as Oscar Wilde once said, and this book is no exception. The cover starts well. It is a reproduction of an Escher trompe-l’oeil etching, showing the remains of snow, with melting footprints and tyre-tracks. Underneath appear to be a perfect set of reflections of trees. Slightly perplexingly, in what appears to be a wintry scene, some of the trees are in leaf. Are they evergreens? But then one notices that the tree trunks appear to grow downwards, as if out of the sludge, but they do not have trunks above ground level. The reflections appear real enough, yet have no actual trees as their source. Perhaps the artist, tantalizing the viewer with a mixture of realism and fantasy, is making the point that appearance and reality are twins, children of stylistic conventions which we ignore at our peril. The book, a collection of eleven essays on various aspects of transportation, focuses on possible ways of minimizing greenhouse gas emissions. It devotes most of its space to a discussion of the ‘promising technologies’
71
Book reviews
that have the potential of facilitating significant reductions in CO* and other greenhouse gases in the transportation sector. Seven of the eleven chapters deal with fuel and possible technological fixes to greenhouse emissions. The essays are drawn from a Conference held in 1991, at the Asilomar Centre in Pacific Grove, California, to discuss global warming. There is an attempt to give the book a structure by putting general essays at the beginning and the end. Such attempts to broaden the themes are somewhat disappointing. The first essay, ‘Highway Vehicle Activity Trends and Their Implications for Global Warming: the United States in an International Context’ by Michael P Walsh, for instance, offers a clear exposition of the chemistry and so environmental implications of vehicular emissions. But this chapter does not attempt to live up to any of the more ambitious goals suggested by its title. It does not explore, for instance, any of the social, economic or political implications of emissions, in the developed or less developed worlds. The focus is on statistics on various trends such as vehicle populations (sic) and emissions scenarios. The failure to explore policy issues in any depth means the book does not have the sort of beginning, middle and end structure that would make it, for me at least, an easy read. There is no thesis to pursue, no set of arguments to unravel and no range of types of argument that separates one essay from another. The absence of any protracted discussion on the social dimensions of the issues may be because the organizers of the conference were unable to reach any agreement on a recommended ‘no regrets’ policy on CO2 emissions. A ‘no regrets’ policy is required to be worth doing even if its COZ. reduction benefits have no value. Perhaps the failure to reach agreement, which is briefly discussed in the Foreword, stymied the editors. Perhaps the problem is also one of reading a book whose authors almost exclusively work in North America in a European context. Clearly the debates and the issues
72
are very different in the two continents. The feeling in Transportation and Global Climate Change is one of impotence. Various authors assert that there more are environmentally friendly fuels that could be manufactured - for instance there is a chapter called ‘Characteristics of Future Aviation Fuels’ which discusses hydrogen, methane, propane n-butane, ethanol and methanol as potential aviation fuels, but there is a resigned tone of muted despair about the possibility of these technological innovations ever being implemented. This chapter concludes: ‘Unless there’s a real petroleum shortage or there are politically imposed costs, alternative fuels will cost more than petroleum-based fuels’. (P281) As a conclusion to a whole chapter on such alternative fuels, this seems an alarmingly self-defeating admission. But other contributors share a similar perspective: John Mason, author of Chapter 5 ‘IC [Internal Combustion] Engines and Fuels for Cars and Light Trucks: 20 15, somewhat disarmingly confesses: ‘The title notwithstanding, this chapter contains no predictions with respect to what will happen by the year 2015. Rather the purpose is to indicate what could be done technologically by 2015 if the market and economic conditions were right’. (P 127) These ‘ifs’ about market and economic conditions are big. But they are vital. I was left wondering what model of science - or indeed life motivates these people who are beavering away producing knowledge that they seem happy to admit is at worst an irrelevance and, at best, a small fragment of what needs to be a much larger picture. In the following example from the fascinating chapter ‘The Effects of Transportation Growth in Four Asian Cities’, there is a reach for technology type response where it seems inappropriate. The authors have stepped outside of the technological focus of many of the other chapters, describing how each city faces particular challenges, for example, arising from infrastructural needs, growth, lack of coordination and the
relative availability of oil, and so raising political and policy questions. They also describe how in Surabaya, Indonesia, the local people have an extensive fleet of becaks, humanpowered bicycle taxis which are ideal for moving people and light freight and, of course, are non-polluting, provide employment and are, in themselves, relatively safe. The Government of Indonesia is actively discouraging this form of transport as outdated and a trafftc impediment. In 1989 it went so far as to round up 100000 becaks and threw them into the sea. Birk and Reilly-Roe write in their conclusion: . . . each team has been struggling to find useful information and has had diffkulty analysing it and using it themselves. When it comes to air pollution, for example, it is just as important to make improvements to two- and three-wheeled vehicles as to fourwheeled vehicles. Technology is available to reduce this problem at low cost. (p 103)
The need seems less for technology and more for a politics that values human health, the environment and the safety of those unable or unwilling to afford cars (admittedly unlikely in the context of the Indonesian Government’s appalling human rights record). The sense that technology is unproblematic is linked to the book’s preoccupation with a technological, fuel based, solution to the world’s transportation problems. I do not think that there will be a solution coming from this area. Clearly, issues about cultural diversity, quality of life and the social degradation of current levels of travel need to be addressed. Studies show, for instance, that there is an inverse relationship between people talking on a street and the amount of traffic running through it. As cars increase, human community life, of some particular kinds, decreases. This book has stopped at the level of presenting facts, which raises the issue of linking facts and values. The division between facts and values is rooted in recent western history and needs to be challenged if we are not to consign good brains, such as those of these authors, to the cul-desac of producing endless facts which attempt to, but can not begin to
Book reviews
unlock the reasons why there is not consensus or change. movement, This book is the product of an implicit ‘fact/value’ dichotomy, which means that facts are not seen in the contexts of values such as particular interests and power - but, instead, are treated as free floating entities. Perhaps this is why the attempt to secure agreement on a ‘no regrets’ policy failed. For at the end of the day there are costs: it is a Faustian (and capitalist) dream that we can go on exploiting human or natural resources without any repercussions. The question is, whose costs get counted? Whose ‘facts’ get repreThese need sented? questions answers. Unfortunately this book does not provide them. I believe such technological discussions do need to be informed by awareness of the social context which give rise to their generation of facts to be truly useful. This book is full of sincerity. It is packed full of interesting facts, and worthy essays. Is this enough? It depends, of course, on the purpose required. For those seeking elucidation on the basic issues surrounding greenhouse gases and vehicular emissions, models, projections and possible technologically based solutions, this will be a treasure trove, albeit a somewhat dated one. (Most of the tables only contain data from the mid-1980s and there are some recent concerns, such as the environmental implications of battery disposal if there was a largescale switch to electric vehicles, which are not included). For my money, the best books are interventions in current debates. They develop a new way of seeing the world: a new vision of reality. This book is too coy about dismantling the social and political issues of its own science and the barriers to effectiveness in the research areas it discusses, to be able to move the transportation debate forward. It is good, but does not unpack enough appearances to make people stop and take notice. Amanda Root Environmental Change Unit, Oxford University, UK
RESOURCE MANAGEMENT INFORMATION SYSTEMS. PROCESS AND PRACTICE by Keith R McCloy Taylor and Francis, London, 415pp, f29.50 paperback
7995,
ISBN o-7484-0120-2
A large number of books have been published on remote sensing since the important introductory text to the subject by Lillesand and Kiefer.’ Most of these texts however, place a strong emphasis upon techniques and often fail to address much broader questions of resource management of interest to geographers, foresters, agronomists and others with an interest in the planning of land and management resources. A potential danger with a book which aims to describe ‘the role of information systems in supporting the proper management of physical environmental resources’, is that the huge scope of the topic might result in rather generalized treatment of important techniques and methods. This is not the case with this book, a point which is clear from reading the first chapter on physical principles of remote sensing. This chapter is comprehensive, covering all aspects of the subject scientifically and including clear explanations of terms with good use of diagrams and simple equations. Whilst this is only one chapter of the book, it would form an extremely valuable introduction to the subject for resource managers and students at all levels. Interestingly, where most texts would follow with a chapter on digital image processing, this book follows with a chapter on visual interpretation of both air photography and satellite imagery. This reflects the main aim of the book which is to provide resource managers with practical tools and correctly reflects the continuing importance of visual techniques for the interpretation of both air photography and satellite imagery in resource survey. The chapter is followed by one on the applications of visual interpretation for drainage interpretation, agricultural land capability and soil erodibil-
ity mapping, terrain classification, land use and land cover mapping, and crop inventory. The chapter concludes with an interesting and important section on the value of integrating data from different satellite systems (eg radar and optical data) to improve the information content of imagery. The next chapter on image processing is as comprehensive and detailed as the introductory chapter on the physical principles of remote sensing. The mathematical treatment might be difficult for undergraduate students lacking good mathematical skills, but once again the well written text and good use of diagrams allows for clear understanding. The text reflects the considerable advances in image processing in recent years with a detailed description, for example, of the vector classifier. The absence of references to spatial filtering is curious, however, especially given the important role that high/low pass and directional filtering can play in the enhancement of imagery to assist with image interpretation. This is necessarily a technical chapter and the resource manager faced, for example, with the problems of producing resource maps for a large, poorly mapped country might feel a bit lost. Including a worked example of the cartographic processes involved in the production of image maps for a country-wide resources survey, might have helped in this respect. The chapter on the use of field data is useful in that it provides a link between the preceding chapters, all of which are devoted to the extraction of information from remotely sensed data. The author views field data primarily as spectral data or other data (eg biomass) collected in support of remote sensing programmes, for example to measure map accuracy or for the calibration and validation of models to retrieve biophysical information from the remotely sensed imagery. This illustrates a structural problem with the book, in that there is a tendency to present remotely sensed data as the major source of data for resource management and the associated techniques of image processing as the major analytical tools.
73
developed by illustrating the transferability of pollutants from one medium to another. The second part of the book is concerned with the human health effects of pollutants. The chronological reader is led easily from passages in preceding chapters that are concerned with indoor air pollution and respiratory effects of air pollution into subsequent chapters that deal with a more detailed examination of human health toxicology. Neurotoxicity, carcinogenesis developmental and genetic toxicology are all described taking as a starting point first principles and are developed in enough detail in order that the reader appreciates the particular role played by environmental pollutants in each case. The overview is completed with separate chapters on social issues such as risk assessment and environmental economics and the role of environmental toxicology in regulation and policy considerations. Although this book is not unique in setting itself the task of providing an overview of environmental toxicology, what sets it apart rom existing texts is its accessibility. This is partly accomplished by the clear manner in which it has been written making use of over 100 tables and illustrations. Most helpful though is the liberal use of case studies that are used to illustrate the themes of each chapter. These range from those commonly used to exemplify themes in environmental science such as the case of DDT and PCBs, to lesser known examples illustrating specific problems. What I found most fascinating and particularly instructive in these was their historical dimension, which is frequently omitted when referring to cas cdlibre. Conversely, the book has clearly been written with a North American reader in mind with little reference being made to European or Asian examples of pollution, of which there are many possible to choose from. Overall though this work will, I believe, achieve its aspirations of being a standard introductory text to the field, particularly in the US.
Environmental
Steve Ho//ins Consultant London UK
THE GLOBAL CASINO. AN INTRODUCTION TO ENVIRONMENTAL ISSUES by N Middleton Edward Arnold, London, 1995, 332pp, f15.99 paperback
cial on the human side. The chapter on soil erosion, for example, notes that the driving forces in erosion and conservation are economic, social and political but the chapter gives more detail about the physical processes that the social processes - but at least the social processes are acknowledged and stressed.
ISBN o-340-59493-4
The implications of the title are that ‘environmental issues involve winners and losers’ with the analogy that ‘the casino’s chance elements and the players’ imperfect knowledge of the outcomes of their actions are relevant in that our understanding of how the Earth works is far from perfect’ and also ‘some players can afford to take part.. while others are less able’. An important aspect of the book is ‘its illustration of success as well as ‘horror’ stories’. After the two introductory chapters on the physical and human environment, the book covers deforestation, desertification, food production, soil erosion, threatened species, climatic change, acid rain, oceans, coastal problems, rivers, lakes and wetlands, big dams, urban environments, transenergy waste management, port, production, mining, war and natural hazards, ending with a consideration of conservation and sustainable development. The book is extremely sound, rather than innovative or ground-breaking in its approach, and covers basic theory, examples and illustrations, with a profusion of photographs and diagrams which makes the subject live. The volume should find a ready home in the sixth form and early undergraduate years alike. The real strength lies in the fact that the book outlines both the workings of the physical environment and the political, economic and social frameworks in which the issues occur. This immediately lays the book open to the possibility that it can be criticized for being superficial or naive on either the physical or the human side, but I think that, in fact, the book manages to achieve a very reasonable balance between the two aspects, though perhaps tending towards being superti-
Stephen Trudgill Reader in Geography University of Sheffield, UK
TRANSPORTATION AND GLOBAL CLIMATE CHANGE edited by David L Greene and Danilo J Santini American Council Efficient Economy, 1993, tJS$28.00
for an EnergyWashington, DC,
ISBN O-918249-17-1
‘In matters of grave importance, style, not sincerity is the vital thing’, as Oscar Wilde once said, and this book is no exception. The cover starts well. It is a reproduction of an Escher trompe-l’oeil etching, showing the remains of snow, with melting footprints and tyre-tracks. Underneath appear to be a perfect set of reflections of trees. Slightly perplexingly, in what appears to be a wintry scene, some of the trees are in leaf. Are they evergreens? But then one notices that the tree trunks appear to grow downwards, as if out of the sludge, but they do not have trunks above ground level. The reflections appear real enough, yet have no actual trees as their source. Perhaps the artist, tantalizing the viewer with a mixture of realism and fantasy, is making the point that appearance and reality are twins, children of stylistic conventions which we ignore at our peril. The book, a collection of eleven essays on various aspects of transportation, focuses on possible ways of minimizing greenhouse gas emissions. It devotes most of its space to a discussion of the ‘promising technologies’
71
Book reviews
that have the potential of facilitating significant reductions in CO* and other greenhouse gases in the transportation sector. Seven of the eleven chapters deal with fuel and possible technological fixes to greenhouse emissions. The essays are drawn from a Conference held in 1991, at the Asilomar Centre in Pacific Grove, California, to discuss global warming. There is an attempt to give the book a structure by putting general essays at the beginning and the end. Such attempts to broaden the themes are somewhat disappointing. The first essay, ‘Highway Vehicle Activity Trends and Their Implications for Global Warming: the United States in an International Context’ by Michael P Walsh, for instance, offers a clear exposition of the chemistry and so environmental implications of vehicular emissions. But this chapter does not attempt to live up to any of the more ambitious goals suggested by its title. It does not explore, for instance, any of the social, economic or political implications of emissions, in the developed or less developed worlds. The focus is on statistics on various trends such as vehicle populations (sic) and emissions scenarios. The failure to explore policy issues in any depth means the book does not have the sort of beginning, middle and end structure that would make it, for me at least, an easy read. There is no thesis to pursue, no set of arguments to unravel and no range of types of argument that separates one essay from another. The absence of any protracted discussion on the social dimensions of the issues may be because the organizers of the conference were unable to reach any agreement on a recommended ‘no regrets’ policy on CO2 emissions. A ‘no regrets’ policy is required to be worth doing even if its COZ. reduction benefits have no value. Perhaps the failure to reach agreement, which is briefly discussed in the Foreword, stymied the editors. Perhaps the problem is also one of reading a book whose authors almost exclusively work in North America in a European context. Clearly the debates and the issues
72
are very different in the two continents. The feeling in Transportation and Global Climate Change is one of impotence. Various authors assert that there more are environmentally friendly fuels that could be manufactured - for instance there is a chapter called ‘Characteristics of Future Aviation Fuels’ which discusses hydrogen, methane, propane n-butane, ethanol and methanol as potential aviation fuels, but there is a resigned tone of muted despair about the possibility of these technological innovations ever being implemented. This chapter concludes: ‘Unless there’s a real petroleum shortage or there are politically imposed costs, alternative fuels will cost more than petroleum-based fuels’. (P281) As a conclusion to a whole chapter on such alternative fuels, this seems an alarmingly self-defeating admission. But other contributors share a similar perspective: John Mason, author of Chapter 5 ‘IC [Internal Combustion] Engines and Fuels for Cars and Light Trucks: 20 15, somewhat disarmingly confesses: ‘The title notwithstanding, this chapter contains no predictions with respect to what will happen by the year 2015. Rather the purpose is to indicate what could be done technologically by 2015 if the market and economic conditions were right’. (P 127) These ‘ifs’ about market and economic conditions are big. But they are vital. I was left wondering what model of science - or indeed life motivates these people who are beavering away producing knowledge that they seem happy to admit is at worst an irrelevance and, at best, a small fragment of what needs to be a much larger picture. In the following example from the fascinating chapter ‘The Effects of Transportation Growth in Four Asian Cities’, there is a reach for technology type response where it seems inappropriate. The authors have stepped outside of the technological focus of many of the other chapters, describing how each city faces particular challenges, for example, arising from infrastructural needs, growth, lack of coordination and the
relative availability of oil, and so raising political and policy questions. They also describe how in Surabaya, Indonesia, the local people have an extensive fleet of becaks, humanpowered bicycle taxis which are ideal for moving people and light freight and, of course, are non-polluting, provide employment and are, in themselves, relatively safe. The Government of Indonesia is actively discouraging this form of transport as outdated and a trafftc impediment. In 1989 it went so far as to round up 100000 becaks and threw them into the sea. Birk and Reilly-Roe write in their conclusion: . . . each team has been struggling to find useful information and has had diffkulty analysing it and using it themselves. When it comes to air pollution, for example, it is just as important to make improvements to two- and three-wheeled vehicles as to fourwheeled vehicles. Technology is available to reduce this problem at low cost. (p 103)
The need seems less for technology and more for a politics that values human health, the environment and the safety of those unable or unwilling to afford cars (admittedly unlikely in the context of the Indonesian Government’s appalling human rights record). The sense that technology is unproblematic is linked to the book’s preoccupation with a technological, fuel based, solution to the world’s transportation problems. I do not think that there will be a solution coming from this area. Clearly, issues about cultural diversity, quality of life and the social degradation of current levels of travel need to be addressed. Studies show, for instance, that there is an inverse relationship between people talking on a street and the amount of traffic running through it. As cars increase, human community life, of some particular kinds, decreases. This book has stopped at the level of presenting facts, which raises the issue of linking facts and values. The division between facts and values is rooted in recent western history and needs to be challenged if we are not to consign good brains, such as those of these authors, to the cul-desac of producing endless facts which attempt to, but can not begin to
Book reviews
unlock the reasons why there is not consensus or change. movement, This book is the product of an implicit ‘fact/value’ dichotomy, which means that facts are not seen in the contexts of values such as particular interests and power - but, instead, are treated as free floating entities. Perhaps this is why the attempt to secure agreement on a ‘no regrets’ policy failed. For at the end of the day there are costs: it is a Faustian (and capitalist) dream that we can go on exploiting human or natural resources without any repercussions. The question is, whose costs get counted? Whose ‘facts’ get repreThese need sented? questions answers. Unfortunately this book does not provide them. I believe such technological discussions do need to be informed by awareness of the social context which give rise to their generation of facts to be truly useful. This book is full of sincerity. It is packed full of interesting facts, and worthy essays. Is this enough? It depends, of course, on the purpose required. For those seeking elucidation on the basic issues surrounding greenhouse gases and vehicular emissions, models, projections and possible technologically based solutions, this will be a treasure trove, albeit a somewhat dated one. (Most of the tables only contain data from the mid-1980s and there are some recent concerns, such as the environmental implications of battery disposal if there was a largescale switch to electric vehicles, which are not included). For my money, the best books are interventions in current debates. They develop a new way of seeing the world: a new vision of reality. This book is too coy about dismantling the social and political issues of its own science and the barriers to effectiveness in the research areas it discusses, to be able to move the transportation debate forward. It is good, but does not unpack enough appearances to make people stop and take notice. Amanda Root Environmental Change Unit, Oxford University, UK
RESOURCE MANAGEMENT INFORMATION SYSTEMS. PROCESS AND PRACTICE by Keith R McCloy Taylor and Francis, London, 415pp, f29.50 paperback
7995,
ISBN o-7484-0120-2
A large number of books have been published on remote sensing since the important introductory text to the subject by Lillesand and Kiefer.’ Most of these texts however, place a strong emphasis upon techniques and often fail to address much broader questions of resource management of interest to geographers, foresters, agronomists and others with an interest in the planning of land and management resources. A potential danger with a book which aims to describe ‘the role of information systems in supporting the proper management of physical environmental resources’, is that the huge scope of the topic might result in rather generalized treatment of important techniques and methods. This is not the case with this book, a point which is clear from reading the first chapter on physical principles of remote sensing. This chapter is comprehensive, covering all aspects of the subject scientifically and including clear explanations of terms with good use of diagrams and simple equations. Whilst this is only one chapter of the book, it would form an extremely valuable introduction to the subject for resource managers and students at all levels. Interestingly, where most texts would follow with a chapter on digital image processing, this book follows with a chapter on visual interpretation of both air photography and satellite imagery. This reflects the main aim of the book which is to provide resource managers with practical tools and correctly reflects the continuing importance of visual techniques for the interpretation of both air photography and satellite imagery in resource survey. The chapter is followed by one on the applications of visual interpretation for drainage interpretation, agricultural land capability and soil erodibil-
ity mapping, terrain classification, land use and land cover mapping, and crop inventory. The chapter concludes with an interesting and important section on the value of integrating data from different satellite systems (eg radar and optical data) to improve the information content of imagery. The next chapter on image processing is as comprehensive and detailed as the introductory chapter on the physical principles of remote sensing. The mathematical treatment might be difficult for undergraduate students lacking good mathematical skills, but once again the well written text and good use of diagrams allows for clear understanding. The text reflects the considerable advances in image processing in recent years with a detailed description, for example, of the vector classifier. The absence of references to spatial filtering is curious, however, especially given the important role that high/low pass and directional filtering can play in the enhancement of imagery to assist with image interpretation. This is necessarily a technical chapter and the resource manager faced, for example, with the problems of producing resource maps for a large, poorly mapped country might feel a bit lost. Including a worked example of the cartographic processes involved in the production of image maps for a country-wide resources survey, might have helped in this respect. The chapter on the use of field data is useful in that it provides a link between the preceding chapters, all of which are devoted to the extraction of information from remotely sensed data. The author views field data primarily as spectral data or other data (eg biomass) collected in support of remote sensing programmes, for example to measure map accuracy or for the calibration and validation of models to retrieve biophysical information from the remotely sensed imagery. This illustrates a structural problem with the book, in that there is a tendency to present remotely sensed data as the major source of data for resource management and the associated techniques of image processing as the major analytical tools.
73