% @(#)computgrid.hlq	19.1 (ESO-IPG) 02/25/03 13:30:31 
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SECTION./GRID
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COMPUTE/GRID                                                   20-Aug-1985 DB
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COMPUTE/GRID angle
	create image and table with distorted rect. and evenly spaced grid
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Purpose: 
          Create image with distorted but otherwise rectangular and evenly 
          spaced grid plus a table with the points defining the grid. 
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          The grid image is displayed and the grid table also plotted.
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Syntax:   
          COMPUTE/GRID angle
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          angle = distortion angle of the grid (in degrees),
                  defaulted to 1.E-5, which  gives a slight exaggeration of 
                  the distortion typically found in PCD and ST-FOC image
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Note: 
          Size of both image (510 x 510 pixels) and table (81 rows) are fixed.
          For most tests it may be advisable to EXTRACT a subframe of the 
          image.
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          In order to simulate point spread functions with a larger FWHM, the 
          image may be FILTERed.
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Examples:
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          COMPUTE/GRID 0.00002
           Create image GRID.bdf with distorted grid and the table GRID.tbl
           with the points defining the grid.
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           Load the image GRID.bdf and plot the table GRID.tbl .
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