Engineering soil mapping from airphotos

Abstract

Southern Africa, rapidly developing but short of highly trained technicians particularly in the civil engineering field, has of recent years turned more and more to airphoto interpretation as the tool for terrain evaluation, enabling large areas to be identified, classified and evaluated with the barest minimum of field work. The preparation of detailed engineering soil maps, showing drainage pattern, soil type and classification and construction material availability, has become routine in Rhodesia; particularly on bridge, airfield, road and dam construction projects. With the necessity of producing trained staff in the shortest possible time, methods of data storage have become vital. In Rhodesia an index system, built up from experience, has been prepared and is available to the interpreter. By referring to a simple form of card index system on which are recorded similar geological, topographical, climatical and drainage patterns, he can obtain the necessary information to enable him to undertake airphoto evaluation of an area even though he may never have had previous experience with the type of country or geology in which his assignment falls.