752 merge sky region

CHANGELOG.md

@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 #### Changed
 
 - Updated changelog release instructions to remove each release having an empty "Unreleased" section at the start [#772](https://github.com/askap-vast/vast-pipeline/pull/772)
+- Search in a 10 arcsec radius for an existing SkyRegion when adding new images (#759](https://github.com/askap-vast/vast-pipeline/pull/759)
 
 #### Fixed
 
@@ -23,6 +24,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 #### List of PRs
 
 - [#772](https://github.com/askap-vast/vast-pipeline/pull/772): fix, docs: Fixed changelog formatting and updated changelog release instructions
+- [#759](https://github.com/askap-vast/vast-pipeline/pull/759): feat: Do a cone search for existing SkyRegions when adding new images
 
 ## [1.1.1](https://github.com/askap-vast/vast-pipeline/releases/v1.1.1) (2024-10-15)
 

vast_pipeline/models.py

@@ -226,6 +226,38 @@ def __str__(self):
         return self.name
 
 
+class SkyRegionQuerySet(models.QuerySet):
+
+    def cone_search(
+        self, ra: float, dec: float, radius_deg: float
+    ) -> models.QuerySet:
+        """
+        Return all the Sources withing radius_deg of (ra,dec).
+        Returns a QuerySet of Sources, ordered by distance from
+        (ra,dec) ascending.
+
+        Args:
+            ra: The right ascension value of the cone search central
+                coordinate.
+            dec: The declination value of the cone search central coordinate.
+            radius_deg: The radius over which to perform the cone search.
+
+        Returns:
+            Sources found withing the cone search area.
+        """
+        return (
+            self.extra(
+                select={
+                    "distance": "q3c_dist(centre_ra, centre_dec, %s, %s) * 3600"
+                },
+                select_params=[ra, dec],
+                where=["q3c_radial_query(centre_ra, centre_dec, %s, %s, %s)"],
+                params=[ra, dec, radius_deg],
+            )
+            .order_by("distance")
+        )
+
+
 class SkyRegion(models.Model):
     run = models.ManyToManyField(Run)
 
@@ -238,6 +270,8 @@ class SkyRegion(models.Model):
     y = models.FloatField()
     z = models.FloatField()
 
+    objects = SkyRegionQuerySet.as_manager()
+
     def __str__(self):
         return f'{round(self.centre_ra, 3)}, {round(self.centre_dec, 3)}'
 

vast_pipeline/pipeline/utils.py

@@ -37,27 +37,38 @@
 dask.config.set({"multiprocessing.context": "fork"})
 
 
-def get_create_skyreg(image: Image) -> SkyRegion:
+def get_create_skyreg(image: Image, radius: float = 10.) -> SkyRegion:
     '''
-    This creates a Sky Region object in Django ORM given the related
-    image object.
+    This creates a SkyRegion object in Django ORM given the related
+    image object. If a SkyRegion already exists and has an image radius
+    within `radius` arcsec of the input image then use that SkyRegion.
 
     Args:
         image: The image Django ORM object.
+        radius: Search radius (in arcsec) for matching to existing SkyRegion
 
     Returns:
         The sky region Django ORM object.
     '''
-    # In the calculations below, it is assumed the image has square
+    # NOTE: In the calculations below, it is assumed the image has square
     # pixels (this pipeline has been designed for ASKAP images, so it
     # should always be square). It will likely give wrong results if not
-    skyregions = SkyRegion.objects.filter(
-        centre_ra=image.ra,
-        centre_dec=image.dec,
-        xtr_radius=image.fov_bmin
+
+    # Get SkyRegions and image radii areas within `radius` arcsec
+    radius_deg = radius/3600.
+    skyregions = SkyRegion.objects.cone_search(
+        ra=float(image.ra),
+        dec=float(image.dec),
+        radius_deg=float(radius_deg)
+    ).filter(
+        xtr_radius__range=(
+            image.fov_bmin - radius_deg/2.,
+            image.fov_bmin + radius_deg/2.
+        )
     )
     if skyregions:
-        skyr = skyregions.get()
+        # Get the closest in case of multiple matches.
+        skyr = skyregions[0]
         logger.info('Found sky region %s', skyr)
     else:
         x, y, z = eq_to_cart(image.ra, image.dec)