[gdal-dev] GetGeoTransform() valid?

[Frank Warmerdam]

Wim,

I have remove the comment you quoted.  It is from the distant past.  What
you should understand is that this isn't the *only* way to express
georeferencing for GDAL images.  You can also use Ground Control Points,
RPCs and geolocation arrays.  However GeoTransforms are the most common way
and sufficient for many situations.

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)

Best regards,
Frank



On Tue, Apr 23, 2013 at 4:37 AM, Wim de Vries <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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