Updating of soil map of mountaneous regions of Uzbekistan

Abstract

: One of the latest updates on the soil cover of the mountain regions of Uzbekistan is contained in the “Atlas of the Soil Cover of the Republic of Uzbekistan”, published in 2010. It contains soil maps of the regions of the country at the scales of 1 : 350 000 to 1 : 2 500 000 and provides brief charateristics of the soils. The Atlas was compiled on the basis of traditional methods of soil mapping. As a result, its contour part is typical of maps of the mentioned scales and rather schematic. The aim of the research was to update the contour part of the soil maps of mountain territories of Uzbekistan, contained in this Atlas, by means of the analysis of Landsat 8 satellite data. The contour part of the map was updated for the territory with absolute terrain altitude exceeding 900 m. Updating of the map contours was based on the methods of interactive indirect interpretation, when the boundaries of the contours were specified in the GIS using as a substrate the color composites of satellite data obtained at the optimal time of survey. Map correction, mountainous area delineation, and area counting were performed using the GIS ILWIS v.3.3 software package. About 18% of all soil mapping units were divided into several subunits. For 37% of the soil mapping units the boundaries changed significantly (the area of the units changed – by more than 30% with an average change in the length of the boundary of 15–38%). For 45% of soil mapping units the boundaries had changed less significantly (the area of the units had changed by no more than 30% and the boundary length had changed by no more than 20%). No cases of merging of soil mapping units were recorded. As a result, the contour part of the corrected map, compared to the original one, became much more detailed with more indented boundaries. The updated map shows the natural soil cover, excluding the anthropogenically changed soils. But the approach used for updating the original soil map may be also applied to expand the information on anthropogenical load as well. Moreover, this information can be obtained by interpretation of the same satellite data that were used for the map updating.