[Gdal-dev] RPCs

[Frank Warmerdam]

On Mon, 6 Dec 2004 12:49:16 -0500, William Lyons
<wlyons at prologic-inc.com> wrote:
> Frank and List,
> 
> I noticed to my surprise and delight that there is a critter called
> GDALRPCTransformer.  I'm not sure about the path to using the
> transformer though.  So, someone please correct me if I'm wrong.  If
> were to open an NITF file with RPCs in the header the RPC info would be
> put in the metadata for that dataset.  Then I could extract the RPC info
> from the metadata and use that info to construct a GDALRPCTransformer
> object.  Could that object then be used to warp the dataset?

William,

Yes, that is correct. 

Note that currently the GDALRPCTransformer class does not have a
mechanism to pick up elevation data, so it assumes an elevation of 0.0
over the whole image.  This makes it inappropriate for precision 
rectification of images, but it is still useful for a quick and dirty 
rectification. 

With some additional coding it should also be possible to supply the
elevations as needed, but that might be a bit hairy.   Currently NITF
files with RPC00B segments are the only supported source of
RPC data, but I hope someday to extend it to a variety of other
formats. 

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