Utils method to parse coordinates

Author: snbianco

astroquery/mast/collections.py

@@ -19,7 +19,7 @@
 
 from astropy.table import Table, Row
 
-from ..utils import commons, async_to_sync
+from ..utils import async_to_sync
 from ..utils.class_or_instance import class_or_instance
 from ..exceptions import InvalidQueryError, MaxResultsWarning, InputWarning
 
@@ -204,7 +204,7 @@ def query_region_async(self, coordinates, *, radius=0.2*u.deg, catalog="Hsc",
         """
 
         # Put coordinates and radius into consistent format
-        coordinates = commons.parse_coordinates(coordinates)
+        coordinates = utils.parse_coordinates(coordinates)
 
         # if radius is just a number we assume degrees
         radius = coord.Angle(radius, u.deg)

astroquery/mast/missions.py

@@ -184,7 +184,7 @@ def query_region_async(self, coordinates, *, radius=3*u.arcmin, limit=5000, offs
         self._validate_criteria(**criteria)
 
         # Put coordinates and radius into consistent format
-        coordinates = commons.parse_coordinates(coordinates)
+        coordinates = utils.parse_coordinates(coordinates)
 
         # if radius is just a number we assume degrees
         radius = coord.Angle(radius, u.arcmin)

astroquery/mast/observations.py

@@ -23,7 +23,7 @@
 from astroquery import log
 from astroquery.mast.cloud import CloudAccess
 
-from ..utils import commons, async_to_sync
+from ..utils import async_to_sync
 from ..utils.class_or_instance import class_or_instance
 from ..exceptions import (InvalidQueryError, RemoteServiceError,
                           NoResultsWarning, InputWarning)
@@ -227,7 +227,7 @@ def query_region_async(self, coordinates, *, radius=0.2*u.deg, pagesize=None, pa
         """
 
         # Put coordinates and radius into consistent format
-        coordinates = commons.parse_coordinates(coordinates)
+        coordinates = utils.parse_coordinates(coordinates)
 
         # if radius is just a number we assume degrees
         radius = coord.Angle(radius, u.deg)
@@ -346,7 +346,7 @@ def query_region_count(self, coordinates, *, radius=0.2*u.deg, pagesize=None, pa
         """
 
         # build the coordinates string needed by ObservationsClass._caom_filtered_position
-        coordinates = commons.parse_coordinates(coordinates)
+        coordinates = utils.parse_coordinates(coordinates)
 
         # if radius is just a number we assume degrees
         radius = coord.Angle(radius, u.deg)

astroquery/mast/tests/test_mast.py

@@ -1157,3 +1157,33 @@ def test_zcut_get_cutouts(patch_post, tmpdir):
     assert isinstance(cutout_list, list)
     assert len(cutout_list) == 1
     assert isinstance(cutout_list[0], fits.HDUList)
+
+
+################
+# Utils tests #
+################
+
+
+def test_utils_parse_coordinates(patch_post):
+
+    def compare_coords(coords1, coords2):
+        assert coords1.ra.deg == coords2.ra.deg
+        assert coords1.dec.deg == coords2.dec.deg
+        assert coords1.frame.name == 'icrs'
+        assert coords2.frame.name == 'icrs'
+
+    # Expected result
+    expected = SkyCoord('266.40498829 -28.93617776', unit='deg')
+
+    # Parse a string
+    coords = mast.utils.parse_coordinates('266.40498829 -28.93617776')
+    compare_coords(coords, expected)
+
+    # Parse a SkyCoord in ICRS frame
+    coords = mast.utils.parse_coordinates(expected)
+    compare_coords(coords, expected)
+
+    # Parse a SkyCoord in galactic frame
+    galactic = SkyCoord('0 0', unit='deg', frame='galactic')
+    coords = mast.utils.parse_coordinates(galactic)
+    compare_coords(coords, galactic.transform_to('icrs'))

astroquery/mast/utils.py

@@ -122,6 +122,32 @@ def resolve_object(objectname):
     return coordinates
 
 
+def parse_coordinates(coordinates):
+    """
+    Convenience function to parse user input of coordinates.
+
+    Parameters
+    ----------
+    coordinates : str or `astropy.coordinates` object, optional
+        The target around which to search. It may be specified as a
+        string or as the appropriate `astropy.coordinates` object.
+
+    Returns
+    -------
+    response : `~astropy.coordinates.SkyCoord`
+        The given coordinates as an `~astropy.coordinates.SkyCoord` object in the ICRS frame.
+    """
+
+    # Parse into SkyCoord object
+    coordinates = commons.parse_coordinates(coordinates)
+
+    # Convert to ICRS frame, if needed
+    if coordinates.frame != 'icrs':
+        coordinates = coordinates.transform_to('icrs')
+
+    return coordinates
+
+
 def parse_input_location(coordinates=None, objectname=None):
     """
     Convenience function to parse user input of coordinates and objectname.
@@ -140,7 +166,8 @@ def parse_input_location(coordinates=None, objectname=None):
     Returns
     -------
     response : `~astropy.coordinates.SkyCoord`
-        The given coordinates, or object's location as an `~astropy.coordinates.SkyCoord` object.
+        The given coordinates, or object's location as an `~astropy.coordinates.SkyCoord` object
+        in the ICRS frame.
     """
 
     # Checking for valid input
@@ -150,11 +177,13 @@ def parse_input_location(coordinates=None, objectname=None):
     if not (objectname or coordinates):
         raise InvalidQueryError("One of objectname and coordinates must be specified.")
 
+    # Resolve object, if given
     if objectname:
         obj_coord = resolve_object(objectname)
 
+    # Parse coordinates, if given
     if coordinates:
-        obj_coord = commons.parse_coordinates(coordinates)
+        obj_coord = parse_coordinates(coordinates)
 
     return obj_coord