The issue of building thematic maps of erosion dissection, despite its wide demand in various fields of human activity (construction of hydraulic structures, transport and housing construction, agriculture), still has no clear rules and instructions, which causes different perceptions of the obtained mapping results by specialists. The purpose of the study is to experimentally identify the change in the index of erosive dissection depending on the scale of the initial data, the size of the cell, the method of constructing the thematic map, etc. The methods used in this research are the method of mathematical statistics, GIS mapping and modelling, spatial analysis, and change detection. For each of the selected methods of thematic mapping, we compiled the cartograms that allow the visual tracking of changes in the elements of the erosion network depending on the geometric characteristics of the scale and cell size. The dimensions and characteristics with optimal results were substantiated. The main feature of erosional dissection mapping of any territory is to detect the negative relief or concave upward forms. The result is a visual perception accompanied by the addition of numerical values. Estimation of erosion dissection by these methods was used in the construction of a thematic map of the foothill territory with a relatively homogeneous relief pattern. It should be noted that the change in the morphometric index happens simultaneously with the change in orographic features. Therefore, for areas with different forms of relief, the combination or use of only one of the above methods allows identifying the optimal and most accurate one among them. The use of well-established methods will facilitate the study of foothill plains or mountainous areas and will allow expanding the scope of the use of thematic maps for applied purposes and forecasting.