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<div class="moz-cite-prefix">Thanks for taking the time to answer.<br>
On 04/24/2013 02:07 AM, Frank Warmerdam wrote:<br>
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...<br>
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cite="mid:CA+YzLBeZ=zH51UJ2Y8pBL2OkUUnsy4xQJaYhE3=Y073krOxw9g@mail.gmail.com"
type="cite">
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<div style="">Is the relationship between your images and
geographic (lat/long) coordinate space affine? If so, a
geotransform will do just fine. (ie. is the pixel spacing
uniform over the image in terms of decimal degrees)</div>
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If I understand you correctly, it cannot be used for e.g. a lambert
conformal > cartesian (eg. bitmap x,y pixels), because lons are
not parallel and lats are bend when being projected.<br>
<br>
regards,<br>
wim<br>
<br>
<br>
BTW; I want to use GDAL for an OS flight navigation project
(<a class="moz-txt-link-freetext" href="http://openflightnav.org/">http://openflightnav.org/</a>)<br>
<br>
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cite="mid:CA+YzLBeZ=zH51UJ2Y8pBL2OkUUnsy4xQJaYhE3=Y073krOxw9g@mail.gmail.com"
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<div style="">Best regards,</div>
<div style="">Frank</div>
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<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Tue, Apr 23, 2013 at 4:37 AM, Wim de
Vries <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:wsvries@xs4all.nl" target="_blank">wsvries@xs4all.nl</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> Hi,<br>
I want to go from x,y (pixels) to lon,lat and vice versa,
using geotiffs.<br>
I have found the <a moz-do-not-send="true"
href="http://www.gdal.org/classGDALDataset.html#af9593cc241e7d140f5f3c4798a43a668"
title="Fetch the affine transformation coefficients."
target="_blank">GetGeoTransform()</a> function, but the
documentations says:<br>
<br>
"NOTE: <a moz-do-not-send="true"
href="http://www.gdal.org/classGDALDataset.html#af9593cc241e7d140f5f3c4798a43a668"
title="Fetch the affine transformation coefficients."
target="_blank">GetGeoTransform()</a> isn't expressive
enough to handle the variety of OGC Grid Coverages
pixel/line to projection transformation schemes.
Eventually this method will be depreciated in favour of a
more general scheme."<br>
<br>
I googled a lot, but cannot find out what is meant exactly
by "OGC Grid Coverages". I am just working with a simple
cartesian x,y grid.<br>
<br>
Anyone willing to explain a bit more.<br>
Thanks.<br>
</div>
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-- <br>
---------------------------------------+--------------------------------------<br>
I set the clouds in motion - turn up | Frank Warmerdam, <a
moz-do-not-send="true" href="mailto:warmerdam@pobox.com"
target="_blank">warmerdam@pobox.com</a><br>
light and sound - activate the windows | <a
moz-do-not-send="true" href="http://pobox.com/%7Ewarmerdam"
target="_blank">http://pobox.com/~warmerdam</a><br>
and watch the world go round - Rush | Geospatial Software
Developer<br>
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