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Last modified: 26 October 2016

URL: http://cxc.harvard.edu/chips/bugs/regions.html

Bugs: regions


Table of Contents

Caveats

Bugs


Caveats

Self-intersecting polygon regions are not supported.

The following self-intersecting lines can be used to create a line:

chips> clear()
chips> x = [0.1, 0.9, 0.9, 0.1, 0.1]
chips> y = [0.1,0.9, 0.1, 0.9, 0.1]
chips> add_line(x, y)
[The points create a rotated hour-glass shape]

but not a region:

chips> add_region(x, y)
chips ERROR: Region creation attempt failed- degenerate polygons (duplicate or intersecting edges) are not supported

Bugs

Regions may have sections missing in postscript or PDF formats

Regions may have sections missing on print out to postscript or PDF formats when sections of the region appear outside the frame or window. To avoid this, ensure the plot displays all the region or, if possible, filter the region so that only those parts within the plot area are used.

For an example of this, see the discussion of the FOV overlay gallery example.


Last modified: 26 October 2016
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