[Gdal-dev] NITF RPC Support

[Frank Warmerdam]

Folks,

I have implemented some degree of support for Rational Polynomials for
providing georeferencing information of a raster.  Currently the only format
from which this can be exploited is NITF (using the RPC00B tags).  The
GDALRPCInfo structure in gdal.h encapsulates the information we keep about
an RPC transformation.  The actual coefficients are currently returned as
metadata.

There is a stub transformer using the RPC information, but it is only
meaningful going from lat/long/height to Pixel/line currently. When the
reverse transform is requested a simple affine approximation is used.
The gdalwarptest program can exploit the RPC but since there is currently
no infrastructure to supply elevation data a zero elevation is always used
... clearly discarding much precision.

While I don't plan to exploit the RPC support fully in the GDAL warp API, or
in OpenEV for the time being, I am interested in adding support in GDAL for
other RPC coefficient formats, and with establishing a defacto standard open
format for RPC coefficients, and/or ways of embedding them into formats like
GeoTIFF.  Input on solutions other have used are of interest.

I would like to thank GeoTango (http://www.geotango.com) who have supported
this work.

Best regards,

-- 
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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