[task #15637] Match RA and Dec catalog to X and Y catalog to find WCS

[Natáli Anzanello]

Follow-up Comment #8, task #15637 (project gnuastro):

Continuing on the task of finding the matches, two small fixes were made on
this fork: https://codeberg.org/ndanzanello/gnuastro/src/branch/astrometry

The first is about a segmentation fault occurring when no match was found. The
second is a fix on the vertices returned when a match was found. It was
returning the matched vertices in the order generated prior to the geometric
approach (Figure 'vertices_after_match.png' shows this).

Now, we're dealing with the problem that the vertices of the quads are not
always the same (Figure '4stars_vertices_distances.png' shows this in a setup
with 4 stars using 30 degrees rotation).

First, we're able to fix this to catalogs without rotation (Figure
'new_dist_4stars.png' shows this after fixing it and 'old_dist_4stars.png' is
prior to the fix). We can note that the hashes are pretty similar after the
fix and the distance between the hashes has gone under 0.01!

But now, the problem is the one given by the '4stars_vertices_distances.png'
figure, ie, when we have to deal with a rotation. I'm still thinking about
this problem and would like to know if you have some suggestions :)

(file #51572, file #51573, file #51574, file #51575)
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Additional Item Attachment:

File name: 4stars_vertices_distances.png  Size:381 KB
   
<https://file.savannah.gnu.org/file/4stars_vertices_distances.png?file_id=51572>

File name: new_dist_4stars.png            Size:28 KB
    <https://file.savannah.gnu.org/file/new_dist_4stars.png?file_id=51573>

File name: vertices_after_match.png       Size:66 KB
   
<https://file.savannah.gnu.org/file/vertices_after_match.png?file_id=51574>

File name: old_dist_4stars.png            Size:27 KB
    <https://file.savannah.gnu.org/file/old_dist_4stars.png?file_id=51575>



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