Google Maps / Virtual Earth map projection in MapServer

[Pietro Giannini]

Hi dave,
for Mercator I use the following inline declaration of projections:

map
...
projection
   "proj=merc"
   "lat_ts=0"
   "lon_0=0"
   "x_0=0"
   "y_0=0"
   "ellps=WGS84"
   "datum=WGS84"
end # of projection
...
end #of map

or also:

map
...
projection
   "proj=merc"
   "lon_0=0"
   "k_0=1"
   "x_0=0"
   "y_0=0"
   "ellps=WGS84"
   "datum=WGS84"
end # of projection
...
end #of map

both have meters as measure unit.

bye
...................pg





> I'm trying to get my map in the same projection that's used by Google Maps
> &
> Virtual Earth.
>
> According to this article:
>
> http://www.sharpgis.net/2007/05/05/SpatialReferencesCoordinateSystemsProjectionsDatumsEllipsoidsConfusing.aspx
>
> the SRS string for the projection used is:
>
> PROJCS["Mercator Spheric", GEOGCS["WGS84based_GCS",
> DATUM["WGS84based_Datum", SPHEROID["WGS84based_Sphere", 6378137, 0],
> TOWGS84[0, 0, 0, 0, 0, 0, 0]], PRIMEM["Greenwich", 0, AUTHORITY["EPSG",
> "8901"]], UNIT["degree", 0.0174532925199433, AUTHORITY["EPSG", "9102"]],
> AXIS["E", EAST], AXIS["N", NORTH]], PROJECTION["Mercator_1SP"],
> PARAMETER["False_Easting", 0], PARAMETER["False_Northing", 0],
> PARAMETER["Central_Meridian", 0], PARAMETER["Latitude_of_origin", 0],
> UNIT["metre", 1, AUTHORITY["EPSG", "9001"]], AXIS["East", EAST],
> AXIS["North", NORTH]]
>
> How can I use this information in my map file to specify the output
> projection of my map? (projections aren't my strong point!)
>
> Thanks,
> Dave.
>


Pietro Giannini
Bytewise srl - Area GIS
41°50'38.58"N 12°29'13.39"E