[Gdal-dev] Reading RPC

[Peng Gao]

Thanks Frank.

Have another question.

I got some tiff images with RPC from Space Imaging. But the RPC
are stored in a separate txt file, instead of as tiff tags. 
If the tiff file name is
x.tif, then the RPC text file name is x_rpc.txt. Can GDAL read RPC
from the text file? How can I tell GDAL the txt file is associated
with the tiff image?

I opened the image, x.tif, and GDAL says it has geotransform but
no RPC.

Thanks,
Gao, Peng



> -----Original Message-----
> From: Frank Warmerdam [mailto:fwarmerdam at gmail.com]
> Sent: Monday, March 28, 2005 7:58 PM
> To: Peng Gao
> Cc: GDAL-dev list
> Subject: Re: [Gdal-dev] Reading RPC
> 
> On Fri, 25 Mar 2005 11:51:02 -0800, Peng Gao <pgao at esri.com> wrote:
> >
> >
> >
> > If  I have an image with RPC (e.g. a NITF image from Space Imaging), how
> do
> > I read the RPC
> >
> > information via GDAL? Is there a function similar to Set/GetGCPs() for
> RPC?
> 
> Peng,
> 
> The RPC information is transported as Metadata text.  You can use the
> GDALExtractRPCInfo() function to extract the metadata and build it into
> a GDALRPCInfo structure suitable for examination or use with the GDAL
> RPC functions.
> 
> You could do something like this:
> 
>   char **papszMD;
>   GDALRPCInfo sRPC;
> 
>   papszMD = GDALGetMetadata(hSrcDS,"");
>   if( GDALExtractRPCInfo( papszMD, &sRPC ) )
>     printf( "Got RPC Info\n" );
> 
> Best regards,
> --
> ---------------------------------------+----------------------------------
> ----
> I set the clouds in motion - turn up   | Frank Warmerdam,
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent