Evaluation of the Cartographic Application of ERTS-I Imagery

Abstract

This paper reports the results of a NASA-sponsored study to examine the overall cartographic potential of ERTS (Earth Resources Technology Satellite). Several specific cartographic experiments by the U.S. Geological Survey (USGS) and a number of other foreign and domestic experiments are analyzed. Additional cartographic applications, such as aeronautical and nautical charting, are also investigated. It is concluded that an ERTS-type satellite has widespread application to a variety of direct mapping tasks-particularly those related to 1:250,000 and smaller-scale mapping. In addition, ERTS imagery indicates areas of change which justify large-scale map revision, and this may be as significant a cartographic application as the direct use of the imagery. By comparing ERTS images of the same area taken one or more years apart or in different seasons, far more cartographic information can be obtained than from the analysis of any single image. This application calls for the continuous operation of an ERTS-type satellite. ERTS is the first system that lends itself to automated mapping from imagery, and this may be the single most important cartographic characteristic of ERTS. As a result of these investigations, it is recommended that ERTS-type satellites be flown continuously for at least a decade. The value of such a program to mankind as a whole in the form of cartographic and related products is believed to outweigh greatly the costs involved. Apparently others join in this view as ERTS-2 was launched on January 22, 1975; at the same time, ERTS-C was authorized and is expected to be launched in 1977 or 1978. Thus, close to a decade of continuous ERTS coverage appears probable.