Break apart Datum from the Geographic Coordinate System

Idea created by joel_cusick on Jan 14, 2012
    • RED_ZMAN
    • dashiell
    • idlewise
    • joel_cusick
    • alexroma
    Projections for the most part have changed little over time.  The opposite is true with datums.  Since the advent of GPS and enhanced knowledge of plate tectonics the National Spatial Reference Frame in the US has updated and will continue to update the reference frames of our National Geodetic Framework.  Hence it makes sence to split the projection from the datum in all your define or project tools.  A user would select UTM Zone X.  Then underneath that choice, a list of Datums to apply.  A Lookup table with 1 to M relationships could stand behind the user's choice, narrowing the appropriate datums.   This related table could be maintained much faster than the current workflows that the projection team must maintain, and provide the user an easier interface to navigate.

    Many software (Trimble Pathfinder Office) do this so the user can simply apply State Plane US Foot and then choose the datum.  This would programmatically remove your company from replicating every coordinate system when a datum change occurs.  Take the latest CORS96 GCS's in ArcGIS 10.  Every StatePlane, Every UTM, Every State Plane GCS was replicted and stored in a confusing and impossible to remeber coordinate folder (State System? or Continental?  

    Free the DATUM!  Datums are the one of the most confusing aspect of GIS.  This would be a major step in simplification.