Display a colour map

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           |CALL  IGCOLM (X1,X2,Y1,Y2,IC1,IC2,ZMIN,ZMAX,CHOPT) |
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Action: This routine allows to display a colour map on the screen. Parameter Description:
X1
X coordinate of 1st corner of the rectangle in world coordinates.
X2
X coordinate of 2nd corner of the rectangle in world coordinates.
Y1
Y coordinate of 1st corner of the rectangle in world coordinates.
Y2
Y coordinate of 2nd corner of the rectangle in world coordinates.
IC1
First colour index.
IC2
Last colour index
ZMIN
Minimum Z value.
ZMAX
Maximum Z value.
CHOPT
Options.
'C'
Draw the levels with Colours.
'B'
Draw the levels with Boxes.
'A'
Draw the Axis.
'H'
Draw the map Horizontally (default is vertically).