[gdal-dev] Using GDALRPCTransform with a pre-loaded DEM

[Julien Osman]

Dear GDAL community,

I use the RPC transformer available in GDAL (GDALCreateRPCTransformer
and GDALRPCTransform).

To provide a DEM to the transformer, one needs to set the option
"RPC_DEM" with the path to the DEM file. In my workflow, this is not
very convenient because the DEM is already loaded in memory as a
GDALDataset. This means that I need to write it to the disk and let
GDALCreateRPCTransformer load it again. In my opinion, it would make
sens to open a little the API so one can provide the DEM directly as a
GDALDataset.

If this is OK for you, I can implement this functionality and propose a
Pull Request. The solution I see would be to add a function
GDALRPCAddDEM, similar to GDALRPCOpenDEM without the part opening the
GDALDataset. What do you think?

Best regards.
Julien Osman.