Help for GRAFIMG

PURPOSE

    grafimg turns a Vicar image into a 3-D IBIS graphics-1 file by drawing
grid lines with z values depending on the pixel values.  The program accepts
a sarting line and sample in the image and a number of lines and samples in 
the image to 'look at' -- they define a window.  Additionally/optionally
one can subsample this window when turning l,s,DN into graphics coordinates.
SINC picks up every SINC'th pixel in the sample direction for conversion.
LINC picks up every LINC'th pixel in the line direction for conversion.
So the following pixels are converted to graphics points:
	SS, SS + SINC, SS + 2*SINC, ...   for sample coordinate
	SL, SL + LINC, SL + 2*LINC, ...   for line coordinates

    The largest grid of sampled points is 256 x 256. If the user specifies 
a window and subsampling that results in a grid larger than 256 x 256, 
then the program automatically chooses an integer subsampling value that 
will map the grid size down to fit inside 256 x 256.  This can be very 
tricky; an initial window of 257 x 257 and subsampling of 1 x 1 will
result in a 128 x 128 grid !  You can lose resolution in both the graphics
domain and the image domain if subsamplings are not chosen consistent with
the window size.

    The output grafics file can also include a cube, in which the data is
contained. Either the top or the bottom or both the top and the bottom of
the cube can be created. The cube will fit the min/max values by default,
but the user may specify the exact min and max if desired. The user may also
clip the creation of output grafics below or above a specific Z value (useful
if the image is a rotate elevation file within an image and contains vast
regions of zero DN). The output data set will also be clipped to the range of
the specified cube.

    The user may view the 3-D data in one of several formats. For a quick
preview of the dataset, the user may specify the PREView option in MODE, which
will create a graphics representation around the 4 sides of the data set
(similar to profile lines across terrain). The user may select DOTS, which will
create a dot at the intersection of the grid cells or PRDT (preview plus dots).
The conventional graphics file is the default, this being the BOTH option which
will create the normal "fishnet" graphics file. Either the XONLY or the YONLY
axis can be specified with the specific option to MODE.

EXECUTION

  grafimg ELEV.IMG ELEV.GRA ZSCALE=100

  grafimg SURFACE.IMG ELEV.3D LINC=5 SINC=5 MODE=PRDT ZMIN=500 ZMAX=2500  			      CUBE=CUBE ZTOP=3500 ZBTM=0


Original Programmer:  Frank Evans		February 1986
Cognizant Programmer: Ted Barragy / Richard Fretz    January 1988
Made portable for UNIX:   CRI                   06-MAR-95

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