Comparison of four independent soil surveys by air-photo interpretation, paphos area (Cyprus)

Abstract

Four skilled soil surveyors from three countries collaborated independently to produce soil maps of 19 km 2 in southwestern Cyprus by air-photo interpretation. No restrictions were imposed on their choice of soil classification, map legend and mapping units. All had access to the same 1:10,000 panchromatic air-photo stereo-cover and to the necessary background information on geology, topography and land use. Each was given full details of the soil profile at 30 sites of his choice. The four maps are presented. Comparisons demonstrate that the four interpreters used quite different strategies for mapping the same soil landscape, to produce soil maps which differed considerably in the percentage purity of their mapping units and the extent to which the variability of soil properties within mapping units was less than that of the landscape as a whole. The purity appears to be inversely related to the number of profile classes and to the uniformity of mapping units. In this area at least it would seem that the quality of soil surveys by air-photo interpretation (a.p.i.) is more sensitive to the surveyor's choice of soil classes and mapping units than to his skill in locating boundaries. Most published comparisons of a.p.i. soil maps have compared only the surveyors' skill in locating boundaries. Quantitative criteria, such as purity and statistical uniformity, can and should also be employed to compare alternative map legends.