Terrain Evaluation

The aim of this book is to meet the need, expressed by T.G.Miller (1967) and others, for a brief, popular, and inexpensive introduction to terrain evaluation. From a start in the years following the World War II, many individuals and organizations caused a wide expansion of the field. Some workers published summaries of their own and related contributions (eg Christian and Stewart 1968, Beckett and Webster 1969, Webster and Beckett 1970), and the proceedings of an important symposium, edited by G.A.Stewart, assembled summaries of the advances to 1968. The first edition of the present work, published in 1973, sought to provide a simple collation and summary of these and related principles, methods and examples for the benefit of those professionally involved in the use and management of land, students, and general readers. Since that time public awareness of the need for environmental conservation and planning has continually grown. This has contributed to extensive developments in most aspects of the subject, especially in classifications of the earth's surface, remote sensing and data processing technologies, and geographical information systems. The preparation of a second edition gives the opportunity to incorporate these changes, to extend the range of topics covered, notably in including terrain processes and the place of vegetation, and to include a wider range of land user interests. The author especially wishes to record here his debt to Dr.John Howard through whom he obtained a greater understanding of the place of vegetation. The emphasis in this book, however, differs from that in their joint book "Phytogeomorphology". Although the land units defined are the same, greater emphasis is placed on the geomorphological than the ecological aspects. This is for two reasons. First, it is written from the point of view of the earth scientist. Secondly, many of the concepts and examples quoted are from areas where the vegatation pattern may be an unreliable guide to landscape classification, either because it is induced, as in the settled parts of North America and western Europe, or because it is absent, as in deserts. To achieve a synthesis within the compass of a relatively short book, it has been necessary to handle many topics with less depth than would be desirable for the specialist. However, it is contended that the value of a general synthesis outweighs this disadvantage, and that consistency and continuity is aided if it is done by a single hand. Mathematical formulae have been kept to a minimum, and most practical techniques have been outlined rather than being described in detail. To compensate for these restrictions, there are many references to the literature. The emphasis throughout is on the physical, rather than the economic, social or legal aspects of the subject.