Different CRS in Use
Information Communities use their own CRS
Different aims of CRS (position, heights)
Different dimensions required (2D, 3D)
Different model approaches (images, raster, matrices, vector...)
Different geometric properties
Different capturing methods (RS, GPS, Field)
Geographical validity (Area of Use)
Historical lineage of CRS
Politics and political systems
(Change of) technical development
New technologies allow/require new CRS