[Gdal-dev] Confusion with gdalwarp
rob at dataflowdesign.com
Thu Jun 19 10:49:51 EDT 2003
>>>>> "Richard" == Richard Greenwood <Rich at greenwoodmap.com> writes:
Thanks for responding. I'm taking Frank's suggestion and rebuilding
using the latest software in CVS but did try your suggestions.
>> I seem to have a misunderstanding about the use of gdalwarp and
>> am hoping that someone can tell me what is wrong. I am trying
>> to prepare a GeoTiff image for use in mapserver.
>> I'm using gdalwarp to project a GeoTiff raster image. The
>> coordinates of the input file are in lat long. After
>> processing the file with gdalwarp, I used gdalinfo to examine
>> the output file. It appears that the coordinate system
>> information is no longer there. Also, the corner coordinates in
>> the output file are in pixels.
>> I was expecting gdalinfo to display information about the
>> projected coordinate system. Also, I expected the corner
>> coordinates to be displayed in projected units (meters). Is
>> this the normal behavior for gdalwarp? I'm concerned that I
>> may have a configuration or build issue.
>> Thanks for your help, Rob
Richard> Do you have your PROJ_LIB environment variable to point
Richard> to the directory holding the "epsg" file.
The epsg file is found and I have used that notation to set the
projection successfully when using proj
Richard> Alternatively you can define it something like: -t_srs
Richard> "+proj=utm +ellps=GRS80 +zone=12 +north +datum=NAD83
Richard> +units=m" (not your zone!). And if it was me, I'd also
Richard> try defining you s_srs, too.
Tried it, same results. I should have added in my original post that
the resulting image file displays correctly so I think that the
projection works correctly.
Thanks for your help,
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