[Issues] Astrometry Overlap Plot Changes

[John P. McFarland]

Hello All,

This is an informational issue.  Certain points regarding the functioning of
the system require clarification.

There has long been an ambiguity concerning what exactly is plotted with the
GAstrometric.inspect() method for the overlap residuals from a GAstrometric
solution.  In order to isolate the residuals from different pointings, I
reconstructed the coordinates of all associations used in the solution so that
they could be plotted against each other with a different color per pointing.  
The side-effect was that most associations had duplicates plotted leading to
visual symmetries and redundant information in the residual plots.  This was an
invalid approach and has now been changed.

The overlap residuals are now plotted as extracted from the residuals catalog:  
pointing_0 - pointings_1..n, pointing_1 - pointings_2..n, etc.  Because each
successive pointing contains one pointing worth of associations less than the
previous pointing, it is inconsistent to attempt to isolate an individual set 
of associations and assign it to a particular pointing.  As a result, the 
overlap plots are now plotted homogeneously with respect to the pointings 
(i.e., only one color for all pointings).

It will be beneficial to isolate the different chips (instead of pointings) in
the overlap plot containing ALL overlapped associations, but this would
require a substantial rewrite to implement.  This will be addressed at a later
date.

I you use the inspect() method of GAstrometric, make sure to update 
$AWEPIPE/astro/text/AstrometryPlot.py to see these changes.  Any comments or 
problems concerning this can be posted to this thread.

Cheers,


-=John