[Gdal-dev] Reproject with Mapserver vs gdalwarp

[Frank Warmerdam]

Jan Hartmann wrote:
> Frank, is there any reason why Gdal doesn't use the epsg-file? Wouldn't 
> it make things easier if it did? In my experience, this double 
> administration can cause problems that are very hard to detect.

Jan,

First, there are a fair number of folks who use GDAL without
PROJ.4, but it is still necessary to be able to expand EPSG
codes into full definitions for translation purposes.

Second, the PROJ.4 epsg definitions are not very complete.  For
translation I need to know things like the EPSG code for the
datum.  Also, PROJ.4 doesn't have the descriptive name for
coordinate systems and components which I use to populate the

Perversely libgeotiff also has it's own copy of the EPSG
definitions, as does PostGIS.

I agree this can be annoying, but I'm not sure what the solution is.

> Even better of course is Howard Butler's web-based approach:
> 
> http://lists.maptools.org/pipermail/gdal-dev/2007-July/013641.html

I'm very excited about spatialreference.org, but I don't think it
solves all problems.  In particular, most software needs to work fine
in a not-internet-connected situation so I don't want to depend on
web services for my basic coordinate systems support.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | President OSGeo, http://osgeo.org