Help for GENGRID2

PURPOSE

     GENGRID2 creates an ibis file containing a grid in the first two
columns.  The user can select the number of columns if more than four
are desired (all will be double precision).  If other types of columns
are desired (say character), they can be joined in the usual way.  In 
addition a skew can be added horizontally or vertically.

     Bilinear interpolation is used to generate the skewed grid between 
the four points.

     To turn the grid into a geom grid, two more columns must be
provided by the user, usually by mapping the first two columns with
PIXMAP using a reference (mapped) image, or by applying PICMTCH4 to
a pair of images.
	   
CALL
     gengrid2 output parms
  WHERE:
     output       is the output ibis table containing a grid in two columns
     parms        specify the size and spacing of the grid


  
OPERATION

The ibis file is generated with IBIS-GEN and the grid points are calculated
by the routine MF3.

Bilinear interpolation is used to generate the skewed grid between 
the four points.

PERFORMANCE

A 1000 x 1000 grid should only take a few seconds.

Restrictions
------------

The ibis file must have at least 8 columns.

Original Programmer: A. L. Zobrist, 04 Sep. 2002
Current Cognizant Programmer: A. L. Zobrist