[geotk] WKT for EPSG:3857 (Google Maps projection)

[Martin Desruisseaux]

Hello Jon

Le 31/03/11 16:42, Jon Blower a écrit :
> We have a user who wants to add the EPSG:3857 projection (as used by web mapping systems like Google Maps etc) to their epsg.properties file.  Does anyone know the correct WKT to use?  He's currently using the WKT from http://spatialreference.org/ref/sr-org/6864/prettywkt/, but apparently this shifts everything by about 14km.

By printing the CRS built from the EPSG database, I get:

PROJCS["WGS 84 / Pseudo-Mercator",
   GEOGCS["WGS 84",
     DATUM["World Geodetic System 1984",
       SPHEROID["WGS 84", 6378137.0, 298.257223563, AUTHORITY["EPSG","7030"]],
       AUTHORITY["EPSG","6326"]],
     PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],
     UNIT["degree", 0.017453292519943295],
     AXIS["Geodetic latitude", NORTH],
     AXIS["Geodetic longitude", EAST],
     AUTHORITY["EPSG","4326"]],
   PROJECTION["Popular Visualisation Pseudo Mercator", AUTHORITY["EPSG","1024"]],
   PARAMETER["Latitude of natural origin", 0.0],
   PARAMETER["Longitude of natural origin", 0.0],
   PARAMETER["False easting", 0.0],
   PARAMETER["False northing", 0.0],
   UNIT["metre", 1.0],
   AXIS["Easting", EAST],
   AXIS["Northing", NORTH],
   AUTHORITY["EPSG","3857"]]


     Martin