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`GeoQuerySet.distance` now allows calculations to/from non-point geodetic geometry fields as allowed on PostGIS 1.5. 

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12312 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Justin Bronn 2010-01-27 23:09:46 +00:00
parent a6a176013a
commit ff6b44980a
2 changed files with 27 additions and 13 deletions
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1
django/contrib/gis/db/models/query.py
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@ -632,6 +632,7 @@ class GeoQuerySet(QuerySet):
# field is geodetic). However, the PostGIS ST_distance_sphere/spheroid()
# procedures may only do queries from point columns to point geometries
# some error checking is required.
if not backend.geography:
if not isinstance(geo_field, PointField):
raise ValueError('Spherical distance calculation only supported on PointFields.')
if not str(Geometry(buffer(params[0].ewkb)).geom_type) == 'Point':

29
django/contrib/gis/tests/distapp/tests.py
View File

@ -148,13 +148,24 @@ class DistanceTest(unittest.TestCase):
if oracle: tol = 2
else: tol = 5
# Now testing geodetic distance aggregation.
hillsdale = AustraliaCity.objects.get(name='Hillsdale')
if not oracle:
# PostGIS is limited to disance queries only to/from point geometries,
# ensuring a TypeError is raised if something else is put in.
self.assertRaises(ValueError, AustraliaCity.objects.distance, 'LINESTRING(0 0, 1 1)')
self.assertRaises(ValueError, AustraliaCity.objects.distance, LineString((0, 0), (1, 1)))
# Testing geodetic distance calculation with a non-point geometry
# (a LineString of Wollongong and Shellharbour coords).
ls = LineString( ( (150.902, -34.4245), (150.87, -34.5789) ) )
if oracle or connection.ops.geography:
# Reference query:
# SELECT ST_distance_sphere(point, ST_GeomFromText('LINESTRING(150.9020 -34.4245,150.8700 -34.5789)', 4326)) FROM distapp_australiacity ORDER BY name;
distances = [1120954.92533513, 140575.720018241, 640396.662906304,
60580.9693849269, 972807.955955075, 568451.8357838,
40435.4335201384, 0, 68272.3896586844, 12375.0643697706, 0]
qs = AustraliaCity.objects.distance(ls).order_by('name')
for city, distance in zip(qs, distances):
# Testing equivalence to within a meter.
self.assertAlmostEqual(distance, city.distance.m, 0)
else:
# PostGIS 1.4 and below is limited to disance queries only
# to/from point geometries, check for raising of ValueError.
self.assertRaises(ValueError, AustraliaCity.objects.distance, ls)
self.assertRaises(ValueError, AustraliaCity.objects.distance, ls.wkt)
# Got the reference distances using the raw SQL statements:
# SELECT ST_distance_spheroid(point, ST_GeomFromText('POINT(151.231341 -33.952685)', 4326), 'SPHEROID["WGS 84",6378137.0,298.257223563]') FROM distapp_australiacity WHERE (NOT (id = 11));
@ -182,6 +193,7 @@ class DistanceTest(unittest.TestCase):
1162619.7297006]
# Testing with spheroid distances first.
hillsdale = AustraliaCity.objects.get(name='Hillsdale')
qs = AustraliaCity.objects.exclude(id=hillsdale.id).distance(hillsdale.point, spheroid=True)
for i, c in enumerate(qs):
self.assertAlmostEqual(spheroid_distances[i], c.distance.m, tol)
@ -195,7 +207,8 @@ class DistanceTest(unittest.TestCase):
def test03c_distance_method(self):
"Testing the `distance` GeoQuerySet method used with `transform` on a geographic field."
# Normally you can't compute distances from a geometry field
# that is not a PointField (on PostGIS).
# that is not a PointField (on PostGIS 1.4 and below).
if not connection.ops.geography:
self.assertRaises(ValueError, CensusZipcode.objects.distance, self.stx_pnt)
# We'll be using a Polygon (created by buffering the centroid