Help for RPCFWD

PURPOSE

     RPCFWD applies an RPC stored in an image label to (lon,lat,elev)
     stored in an ibis file to produce (line,sample) in the ibis file.
     The columns are chosen with a single paranmeter that names the
     (lon,lat,elev,line,sample) columns.  The longitudes greater than
     180.0 degrees are trimmed to negative longitudes to conform with
     NITF standards by subtracting 360.0.  Elevation is in meters.

TAE COMMAND LINE FORMAT

     rpcfwd INP=(A,B) COLS=(C1,C2,C3,C4,C5)
     
     where

     A           is an IBIS file 
     B		 is a VICAR image with a GeoTIFF label with RPC or a
                      standalone ascii GeoTIFF label with RPC
     COLS        are the IBIS file columns (integers) contain-
                      ing the (lon,lat,elev) and to contain the
                      (line,sample) 
OPERATION
   The GeoTIFF label is accessed and the RPC's are read.  The (lon,lat,elv)
   columns of the ibis file are read, then plugged into the RPF's to yield
   the (line,samp) columns.
   

TIMING

     Should be able to map millions if IBIS records in less than
     a minute on a sparc2.
     
RESTRICTIONS

   The maximum number of coordinate points is limited by IBIS table
   size (currently about 10 million?).  Internal to the program,
   dynamic memory allocation is used.


WRITTEN BY:            A. L. Zobrist, 01 March 2005

COGNIZANT PROGRAMMER:  A. L. Zobrist

REVISIONS: 
  Fri Dec 28 2007 wlb switched to USES_ANSI_C AND LIB_CARTO; misc cleanup
  2022-08-10 B. Crocco afids to opensource (untested)
  

PARAMETERS: