If I have an Esri code for a specific Coordinate System, for example "WGS_1984_Web_Mercator_Auxiliary_Sphere", how do I discover what the equivalent Epsg code is for that coordinate system ? Is there some lookup service on the Esri site or a table of equivalences between Esri and Epsg codes somewhere ?
I am interested in such a service not only for Coordinate Systems, but for all geodetic data (datum, projections, operations etc), if it exists.
