[Gdal-dev] simple OGR/python projection question

Frank Warmerdam warmerdam at pobox.com
Tue Oct 4 19:20:42 EDT 2005

On 10/4/05, John C Cartwright <John.C.Cartwright at noaa.gov> wrote:
> Hello All,
> I'm using the OGR python bindings to convert Plate
> Carree(Equirectangular) coordinates in meters to geographic coordinates
> in WGS84.  I'm getting an answer like:
> (-104.99999999546829, 38.999751150159064, 8426.3269814412379)
> I understand that the first two values are longitude and latitude, but I
> don't understand the third term. Can some one explain?


The problem is that internally PROJ.4 only supports plate caree as a
spherical coordinate system, not ellipsoidal. So the large Z value (8.4km)
is the Z difference between the sphere and ellipsoid at the indicated

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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