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<font face="Times New Roman, Times, serif">Hi Jose, Gabor, Andre,<br>
<br>
I got Jose's program running without trouble, and the results are
the same as what I got with gdal. So the problem is not with gdal,
but there is something wrong with my data. I'll make a detailed
use case tomorrow and hope you can have a look at it.<br>
<br>
Jan <br>
<br>
</font>
<div class="moz-cite-prefix">On 01/18/2013 11:51 AM, Jose Gonçalves
wrote:<br>
</div>
<blockquote
cite="mid:CALHLaOTnorvUvAoHm5pxyMskjRGXRNJugW-=rZSJBs62P2VXWg@mail.gmail.com"
type="cite">
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Hello<br>
<br>
I have a program to create GSB files from two long/lat difference
grids in Surfer format.<br>
<a moz-do-not-send="true"
href="http://www.fc.up.pt/pessoas/jagoncal/coordenadas/write_gsb.exe">http://www.fc.up.pt/pessoas/jagoncal/coordenadas/write_gsb.exe</a><br>
<br>
You can check with it. The longitude difference in the input grid
are in the standard way (east positive).<br>
<br>
<br>
Regards<br>
<br>
José A. Gonçalves<br>
<br>
<br>
<br>
<br>
<div class="gmail_quote">2013/1/17 Jan Hartmann <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:j.l.h.hartmann@uva.nl"
target="_blank">j.l.h.hartmann@uva.nl</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> <font face="Times New
Roman, Times, serif">(Sorry for crossposting, don't know
if it is a gdal or proj problem )<br>
<br>
This has been discussed on this list some time ago. I have
been able to create a working nadgrid file with gdal, but
it doesn't return the right coordinates. I did it as
follows:<br>
<br>
- create a 4 band, float32 geotif, each pixel with the
displacements in lat, lon (arcseconds), errorx and errory
(both zero)<br>
- gdal-translate it to ntv2-format.<br>
<br>
The displacements in the geotiff are correct, and proj
returns shifted coordinates when using the ntv2-file, but
not on the right location. I'm really out of my wits.
Could it have something to do with ntv2 using negative
lon-values east of Greenwich? Any help would be
appreciated.<span class="HOEnZb"><font color="#888888"><br>
<br>
Jan </font></span></font><br>
</div>
<br>
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