Help for POLYCLIP

PURPOSE

"polyclip" takes an IBIS graphics-1 file as input and clips the graphics
elements with a specified window. The new clipped data is output into
another graphics file.


EXECUTION

polyclip INPUT.GRA OUTPUT.GRA   MINLINE=901.5 MINSAMP=100.0  				MAXLINE=1000.0 MAXSAMP=333.3

The IBIS graphics-1 file INPUT.GRA is clipped according to the window
coordinates (MINLINE,MAXLINE,MINSAMP,MAXSAMP) and output to OUTPUT.GRA .


polyclip INPUT.GRA OUTPUT.GRA   MINLINE=901.5 MINSAMP=100.0  				MAXLINE=1000.0 MAXSAMP=333.3  'REORIGIN

In this example the output graphics file is reoriginated so that the
output origin is (line,sample)=(1,1) , i.e. (MINLINE-1,MINSAMP-1) is 
subtracted from all of the coordinate.


polyclip INPUT.GRA OUTPUT.GRA   SKIP=3 MINLINE=1 MINSAMP=1  				MAXLINE=1056 MAXSAMP=1204

In this example, the input IBIS graphics-1 file has five "columns" of
which the first two are the coordinate values and the last three
are skipped.  The skipped data is just carried along and does not effect
the clipping on the other two coordinates.  This is used for carrying
along identification information so it can be determined which polygons
were clipped.



Original Programmer:  Leo Bynum		December 1985

Cognizant Programmer:  Frank Evans	April 1986

Revisions
Made portable for UNIX   A. Scop (CRI)  January 1995