[gdal-dev] GetGeoTransform() valid?

[Wim de Vries]

Thanks for taking the time to answer.
On 04/24/2013 02:07 AM, Frank Warmerdam wrote:
...
> 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)
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.

regards,
wim


BTW; I want to use GDAL for an OS flight navigation project 
(http://openflightnav.org/)

>
> Best regards,
> Frank
>
>
>
> On Tue, Apr 23, 2013 at 4:37 AM, Wim de Vries <wsvries at xs4all.nl 
> <mailto:wsvries at xs4all.nl>> wrote:
>
>     Hi,
>     I want to go from x,y (pixels) to lon,lat and vice versa, using
>     geotiffs.
>     I have found the GetGeoTransform()
>     <http://www.gdal.org/classGDALDataset.html#af9593cc241e7d140f5f3c4798a43a668>
>     function, but the documentations says:
>
>     "NOTE: GetGeoTransform()
>     <http://www.gdal.org/classGDALDataset.html#af9593cc241e7d140f5f3c4798a43a668>
>     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."
>
>     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.
>
>     Anyone willing to explain a bit more.
>     Thanks.
>
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>
>
>
> -- 
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, 
> warmerdam at pobox.com <mailto:warmerdam at pobox.com>
> light and sound - activate the windows | http://pobox.com/~warmerdam 
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