[gdal-dev] Converting between datum
Frank Warmerdam
warmerdam at pobox.com
Sun Jun 1 08:01:53 EDT 2008
Andreas Theofilu wrote:
> What I'm doing wrong? Is it the WMS server who gives me a wrong result or is
> there something else I should do to shift my track to the right place?
> Because I understand only the very most basics, I'm lost.
Andreas,
I tried the file, and saw the effect you were seeing (just a simple
gdal_translate track.wms out.tif shows the effect).
I noticed that the .wms file definition was such that non-square
pixels were being requested from the server. I tried changing this to
use square pixels (by adjusting the extents) and things then seemed
to work fine. I examined the actual http requests being made, and as
far as I can see GDAL was requesting the tiles properly in the non-square
pixel case, so I'm guessing the server doesn't handle non-square pixels
properly even though it is expected under the WMS specification. This was
a problem with MapServer's WMS implementation for a few years for instance.
So, try changing your DataWindow definition to:
<DataWindow>
<UpperLeftX>617400</UpperLeftX>
<UpperLeftY>481865</UpperLeftY>
<LowerRightX>626560</LowerRightX>
<LowerRightY>480365</LowerRightY>
<SizeX>916</SizeX>
<SizeY>150</SizeY>
</DataWindow>
BTW, I don't think it is meaningful for you to have <SRS> set to
EPSG:31287 and <CRS> set to EPSG:4326 in your WMS file. This does not
appear to cause any sort of reprojection, so you should really have
both of these set the same (to EPSG:31287).
Best regards,
--
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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 | President OSGeo, http://osgeo.org
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