Help for RPCSCALE

PURPOSE

     RPCFWD applies an RPC scale stored in an image label or in
     an IBIS file column to a (lon,lat,elev,line,samp) grid
     stored in an ibis file.
     
     The reverse operation of unscaling can be acomplished with
     the change of a keyword ('unscale instead of 'scale).  The
     default is to scale if no keyword is given.

TAE COMMAND LINE FORMAT

     rpcscale INP=(A,B) COLS=(C1,C2,C3,C4,C5) 'DIRECTION
     
     where

     A		 is a VICAR image with a GeoTIFF label with RPC or a
                      standalone ascii GeoTIFF label with RPC
     B           is a IBIS file with an RPC grid (5 columns)
     COLS        are the IBIS file columns (integers) contain-
                 ing the (lon,lat,elev,line,sample) 
     DIRECTION   is one of the keywords "SCALE" or "UNSCALE"
     
or

     rpcscale INP=(A,B) COLS=(C1,C2,C3,C4,C5) RPCCOL=C6 'DIRECTION
     
     where

     A		 is an IBIS file with a column containing RPC scale
     B           is a IBIS file with an RPC grid (5 columns)
     COLS        are the IBIS file columns (integers) contain-
                 ing the (lon,lat,elev,line,sample) 
     RPCCOL      is the IBIS file column (integer) containing the
                 RPC scale and offset in file A
     DIRECTION   is one of the keywords "SCALE" or "UNSCALE"
     
OPERATION
   The RPC's are read from the first file.  The (lon,lat,elv,line,samp)
   columns of the ibis file are read, then altered according to the 
   scale-offsets and also taking the direction into account.
   

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, 04 April 2005

COGNIZANT PROGRAMMER:  A. L. Zobrist

REVISIONS: 
Thu Jan  3 2008 wlb switched to USES_ANSI_C AND LIB_CARTO; misc cleanup  
2022-08-04 B. Crocco opensourced from afids (untested)