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How to convert Geometry to Geography ? RRS feed

  • Question

  • please help me  How to convert Geometry to Geography ?
    Wednesday, July 2, 2014 4:16 AM

Answers

  • Hello,

    you can convert it e.g. via the textual representation of the geometry object:

    DECLARE @gm AS Geometry;
    DECLARE @gg AS Geography;
    SET @gm = geometry::STGeomFromText('LINESTRING (0 0, 20 20, 5 5)', 0);
    SET @gg = geography::STGeomFromText(@gm.ToString(), 4326);
    
    SELECT @gg;

    But geography do have a limited coordinate range (-180 .. 180), so ensure your geometry objects are in the same ranges.


    Olaf Helper

    [ Blog] [ Xing] [ MVP]

    • Proposed as answer by Sofiya Li Thursday, July 3, 2014 9:18 AM
    • Marked as answer by Sofiya Li Wednesday, July 9, 2014 7:01 AM
    Wednesday, July 2, 2014 6:06 AM

All replies

  • Hello,

    you can convert it e.g. via the textual representation of the geometry object:

    DECLARE @gm AS Geometry;
    DECLARE @gg AS Geography;
    SET @gm = geometry::STGeomFromText('LINESTRING (0 0, 20 20, 5 5)', 0);
    SET @gg = geography::STGeomFromText(@gm.ToString(), 4326);
    
    SELECT @gg;

    But geography do have a limited coordinate range (-180 .. 180), so ensure your geometry objects are in the same ranges.


    Olaf Helper

    [ Blog] [ Xing] [ MVP]

    • Proposed as answer by Sofiya Li Thursday, July 3, 2014 9:18 AM
    • Marked as answer by Sofiya Li Wednesday, July 9, 2014 7:01 AM
    Wednesday, July 2, 2014 6:06 AM
  • Do you already have geodetic data or are you trying to project a geometric (projected) coordinate system to geography? if you already have geodetic data the uses a well-known geodetic SRID (i.e. in sys.spatial_reference_systems), it's trivial. If you're trying to do reprojection (change the coordinate system) then you'll need a library like OGR2OGR or a product like SAFE software.  

    Cheers, Bob

    Wednesday, July 2, 2014 5:02 PM