Footprint of symbols

Text author:Luděk KrtičkaLast update:2022-07-26

The footprint of a symbol is the area the symbol would cover if it was projected onto the terrain. The size of the footprint, together with information about minimum distances, helps the mapper to assess how many objects can be mapped without compromising map legibility. In the case of areas with a large number of objects, footprints together with minimum distances act as a natural factor of selective generalization.It is typical for many map symbols that the footprint is larger than the object itself. This is mainly due to the combination of the scale of the map and the size of the map symbol, which must be of a certain size to ensure its legibility.

Especially for point symbols we can observe a larger footprint compared to the real size of the mapped object. For line symbols, the width footprint plays a much smaller role. It is far more important to keep the minimum line length, as too short lines could be misinterpreted by the competitor as a different (point) symbol. A common problem is the mapping of small area objects in their real size. It is possible to map these objects if they are important for navigation, but it is always necessary to enlarge them to the minimum required area/footprint to ensure their legibility on the map.