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On 05/21/11 18:06, Frank Warmerdam wrote:</font>
<blockquote cite="mid:4DD7E2EE.8070002@pobox.com" type="cite"><font
face="Times New Roman, Times, serif">Jan,
<br>
<br>
I believe the problem is that the test.tif is south up. The
NTv2 reader
</font>
<font face="Times New Roman, Times, serif"><br>
in PROJ determines the size based on the extents and pixel size
and gets
<br>
mixed up as the extents are upside down. You can flip test.tif
with
<br>
gdalwarp.
<br>
<br>
eg.
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gdalwarp test.tif northup.tif
<br>
<br>
<br>
</font>
</blockquote>
<font face="Times New Roman, Times, serif">Yes, now it works. Just
to be sure: is the result of the flipping correct? The tif file
was created from two point lists, each with a lat-lon coordinate
and the displacement in arcseconds. Gdal_grid converted the lists
into two grid files, with the upper boundary having a smaller
latitude than the lower coordinate. That's OK, as latitude values
decrease when going north, in contrast with projected coordinates.<br>
<br>
Now, what happens when I use gdalwarp on this file? Is the
complete file mirrored? Are the displacements at the right
geographical location?<br>
<br>
Jan</font> <br>
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