[gdal-dev] Reproject raster map in buffer on-the-fly

[Even Rouault]

Le lundi 23 juin 2014 11:49:58, Oliver Eichler a écrit :
> Hi
> 
> I would like to read a region of a raster map and re-project the resulting
> image on-the-fly before it is displayed. I had a look at the GDAL Warp API
> tutorial. And I stumbled across GDALWarpRegionToBuffer() while reading the
> header files. I had a look into the setup functions and found quite a
> variety of GDALCreateGenImgProjTransformer1..3() or
> GDALCreateReprojectionTransformer(). I have to admit that whole stuff
> leaves me a bit clueless.
> 
> Thus my question:
> 
> Is there a tutorial or an open source project that does the same I want to
> do (I parsed the code of QGis without success)?

Oliver,

Yes, you can look at the Warp API tutorial : http://www.gdal.org/warptut.html

The source code of the gdalwarp utility can also be a source of study.

You can warp into a memory dataset (MEM driver) if your image is of reasonable 
size (fit into RAM) and don't want it to be serialized on disk.

Another possibility is to warp into a VRT dataset (possibly in /vsimem/ 
special file system to avoid temporary file) if your dataset is of a bigger 
size.

Best regards,

Even

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