Beside the main subject, this paper will present principals of average graphical weight of thematic map. The algorithm is based on this subject and also on basics of symbol-scaled(2) mapping. Maps are very often overloaded by symbols. The main goal of thematic mapping is to represent the quantitative and qualitative characteristics of the occurrences in geospace. These two factors are combined in this algorithm. Modern GIS software has possibility to create thematic maps by methods of signs, cartograms and cart diagrams. These are very precise maps and they are presenting distinctive occurrence but also very graphical chaotic with lot of overcastted areas that are overloading the map. These are the reasons why it’s necessary to create this algorithm which would give some balance among boundaries of thematic map area.