fix: add possibility to have width > height for ellipses and boxes

cds-astro · Jul 18, 2024 · 6fa2690 · 6fa2690
1 parent b37715e
commit 6fa2690
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Showing 4 changed files with 67 additions and 16 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -16,6 +16,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [unreleased]
 
+## Fixed
+
+* `MOC.from_astropy_regions` now accepts `EllipseSkyRegion` and `RectangleSkyRegion` where
+  width > height.
+
 ## [0.16.1]
 
 ### Fixed

diff --git a/notebooks/02-Creating_MOCs_from_astropy_regions.ipynb b/notebooks/02-Creating_MOCs_from_astropy_regions.ipynb
diff --git a/python/mocpy/moc/moc.py b/python/mocpy/moc/moc.py
@@ -1811,22 +1811,38 @@ def from_astropy_regions(cls, region, max_depth: int):
             )
         if isinstance(region, regions.EllipseSkyRegion):
             center = region.center.icrs
+            if region.width < region.height:
+                a = region.height / 2.0
+                b = region.width / 2.0
+                angle = region.angle
+            else:
+                a = region.width / 2.0
+                b = region.height / 2.0
+                angle = region.angle + Angle("90d")
             return cls.from_elliptical_cone(
                 center.ra,
                 center.dec,
-                a=region.height / 2,
-                b=region.width / 2,
-                pa=region.angle,
+                a=a,
+                b=b,
+                pa=angle,
                 max_depth=max_depth,
             )
         if isinstance(region, regions.RectangleSkyRegion):
             center = region.center.icrs
+            if region.width < region.height:
+                a = region.height / 2.0
+                b = region.width / 2.0
+                angle = region.angle
+            else:
+                a = region.width / 2.0
+                b = region.height / 2.0
+                angle = region.angle + Angle("90d")
             return cls.from_box(
                 center.ra,
                 center.dec,
-                a=region.width / 2,
-                b=region.height / 2,
-                angle=region.angle + Angle("90d"),
+                a=a,
+                b=b,
+                angle=angle,
                 max_depth=max_depth,
             )
         if isinstance(region, regions.PolygonSkyRegion):

diff --git a/python/mocpy/tests/test_moc.py b/python/mocpy/tests/test_moc.py
@@ -664,6 +664,15 @@ def test_from_astropy_regions():
     moc = MOC.from_astropy_regions(ellipse, max_depth=9)
     assert moc.contains_skycoords(center)
     assert round(moc.largest_distance_from_coo_to_vertices(center).to("deg").value) == 3
+    # invert axes in the ellipse
+    ellipse_swapped = regions.EllipseSkyRegion(
+        center,
+        6 * u.deg,
+        3 * u.deg,
+        (-90 + 10) * u.deg,
+    )
+    moc_swapped = MOC.from_astropy_regions(ellipse_swapped, max_depth=9)
+    assert moc_swapped == moc
     # rectangle
     box = regions.RectangleSkyRegion(center, 12 * u.deg, 6 * u.deg, 10 * u.deg)
     moc = MOC.from_astropy_regions(box, max_depth=8)