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Fixed #27497 -- Improved support of geodetic coordinates on SpatiaLite. 

Area function, Distance function, and distance lookups now work with
geodetic coordinates on SpatiaLite.
This commit is contained in:
Sergey Fedoseev 2016-11-16 17:07:36 +05:00 committed by Tim Graham
parent 38a6df555f
commit 986c7d522a
9 changed files with 105 additions and 37 deletions
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1
django/contrib/gis/db/backends/base/features.py
View File

@ -32,6 +32,7 @@ class BaseSpatialFeatures(object):
supports_distance_geodetic = True
supports_length_geodetic = True
supports_perimeter_geodetic = False
supports_area_geodetic = True
# Is the database able to count vertices on polygons (with `num_points`)?
supports_num_points_poly = True

1
django/contrib/gis/db/backends/mysql/features.py
View File

@ -8,6 +8,7 @@ class DatabaseFeatures(BaseSpatialFeatures, MySQLDatabaseFeatures):
supports_add_srs_entry = False
supports_distance_geodetic = False
supports_length_geodetic = False
supports_area_geodetic = False
supports_distances_lookups = False
supports_transform = False
supports_real_shape_operations = False

5
django/contrib/gis/db/backends/spatialite/features.py
View File

@ -6,7 +6,6 @@ from django.utils.functional import cached_property
class DatabaseFeatures(BaseSpatialFeatures, SQLiteDatabaseFeatures):
supports_3d_storage = True
supports_distance_geodetic = False
# SpatiaLite can only count vertices in LineStrings
supports_num_points_poly = False
@ -16,3 +15,7 @@ class DatabaseFeatures(BaseSpatialFeatures, SQLiteDatabaseFeatures):
# which can result in a significant performance improvement when
# creating the database.
return self.connection.ops.spatial_version >= (4, 1, 0)
@cached_property
def supports_area_geodetic(self):
return bool(self.connection.ops.lwgeom_version())

36
django/contrib/gis/db/backends/spatialite/operations.py
View File

@ -19,6 +19,20 @@ from django.utils import six
from django.utils.functional import cached_property
class SpatiaLiteDistanceOperator(SpatialOperator):
def as_sql(self, connection, lookup, template_params, sql_params):
if lookup.lhs.output_field.geodetic(connection):
# SpatiaLite returns NULL instead of zero on geodetic coordinates
sql_template = 'COALESCE(%(func)s(%(lhs)s, %(rhs)s, %%s), 0) %(op)s %(value)s'
template_params.update({
'op': self.op,
'func': connection.ops.spatial_function_name('Distance'),
})
sql_params.insert(1, len(lookup.rhs) == 3 and lookup.rhs[-1] == 'spheroid')
return sql_template % template_params, sql_params
return super(SpatiaLiteDistanceOperator, self).as_sql(connection, lookup, template_params, sql_params)
class SpatiaLiteOperations(BaseSpatialOperations, DatabaseOperations):
name = 'spatialite'
spatialite = True
@ -79,10 +93,10 @@ class SpatiaLiteOperations(BaseSpatialOperations, DatabaseOperations):
'exact': SpatialOperator(func='Equals'),
# Distance predicates
'dwithin': SpatialOperator(func='PtDistWithin'),
'distance_gt': SpatialOperator(func='Distance', op='>'),
'distance_gte': SpatialOperator(func='Distance', op='>='),
'distance_lt': SpatialOperator(func='Distance', op='<'),
'distance_lte': SpatialOperator(func='Distance', op='<='),
'distance_gt': SpatiaLiteDistanceOperator(func='Distance', op='>'),
'distance_gte': SpatiaLiteDistanceOperator(func='Distance', op='>='),
'distance_lt': SpatiaLiteDistanceOperator(func='Distance', op='<'),
'distance_lte': SpatiaLiteDistanceOperator(func='Distance', op='<='),
}
disallowed_aggregates = (aggregates.Extent3D,)
@ -140,19 +154,19 @@ class SpatiaLiteOperations(BaseSpatialOperations, DatabaseOperations):
def get_distance(self, f, value, lookup_type, **kwargs):
"""
Returns the distance parameters for the given geometry field,
lookup value, and lookup type. SpatiaLite only supports regular
cartesian-based queries (no spheroid/sphere calculations for point
geometries like PostGIS).
lookup value, and lookup type.
"""
if not value:
return []
value = value[0]
if isinstance(value, Distance):
if f.geodetic(self.connection):
raise ValueError('SpatiaLite does not support distance queries on '
'geometry fields with a geodetic coordinate system. '
'Distance objects; use a numeric value of your '
'distance in degrees instead.')
if lookup_type == 'dwithin':
raise ValueError(
'Only numeric values of degree units are allowed on '
'geographic DWithin queries.'
)
dist_param = value.m
else:
dist_param = getattr(value, Distance.unit_attname(f.units_name(self.connection)))
else:

37
django/contrib/gis/db/models/functions.py
View File

@ -38,6 +38,10 @@ class GeoFunc(Func):
except (AttributeError, FieldError):
return None
@property
def geo_field(self):
return GeometryField(srid=self.srid) if self.srid else None
def as_sql(self, compiler, connection, **extra_context):
if self.function is None:
self.function = connection.ops.spatial_function_name(self.name)
@ -122,26 +126,34 @@ class Area(OracleToleranceMixin, GeoFunc):
output_field_class = AreaField
arity = 1
def as_sql(self, compiler, connection):
def as_sql(self, compiler, connection, **extra_context):
if connection.ops.geography:
self.output_field.area_att = 'sq_m'
else:
# Getting the area units of the geographic field.
source_fields = self.get_source_fields()
if len(source_fields):
source_field = source_fields[0]
if source_field.geodetic(connection):
geo_field = self.geo_field
if geo_field.geodetic(connection):
if connection.features.supports_area_geodetic:
self.output_field.area_att = 'sq_m'
else:
# TODO: Do we want to support raw number areas for geodetic fields?
raise NotImplementedError('Area on geodetic coordinate systems not supported.')
units_name = source_field.units_name(connection)
else:
units_name = geo_field.units_name(connection)
if units_name:
self.output_field.area_att = AreaMeasure.unit_attname(units_name)
return super(Area, self).as_sql(compiler, connection)
return super(Area, self).as_sql(compiler, connection, **extra_context)
def as_oracle(self, compiler, connection):
self.output_field = AreaField('sq_m') # Oracle returns area in units of meters.
return super(Area, self).as_oracle(compiler, connection)
def as_sqlite(self, compiler, connection, **extra_context):
if self.geo_field.geodetic(connection):
extra_context['template'] = '%(function)s(%(expressions)s, %(spheroid)d)'
extra_context['spheroid'] = True
return self.as_sql(compiler, connection, **extra_context)
class AsGeoJSON(GeoFunc):
output_field_class = TextField
@ -226,7 +238,7 @@ class DistanceResultMixin(object):
def convert_value(self, value, expression, connection, context):
if value is None:
return None
geo_field = GeometryField(srid=self.srid) # Fake field to get SRID info
geo_field = self.geo_field
if geo_field.geodetic(connection):
dist_att = 'm'
else:
@ -275,6 +287,15 @@ class Distance(DistanceResultMixin, OracleToleranceMixin, GeoFuncWithGeoParam):
self.source_expressions.pop(2)
return super(Distance, self).as_oracle(compiler, connection)
def as_sqlite(self, compiler, connection, **extra_context):
if self.spheroid:
self.source_expressions.pop(2)
if self.geo_field.geodetic(connection):
# SpatiaLite returns NULL instead of zero on geodetic coordinates
extra_context['template'] = 'COALESCE(%(function)s(%(expressions)s, %(spheroid)s), 0)'
extra_context['spheroid'] = int(bool(self.spheroid))
return super(Distance, self).as_sql(compiler, connection, **extra_context)
class Envelope(GeoFunc):
arity = 1

2
django/contrib/gis/db/models/query.py
View File

@ -546,7 +546,7 @@ class GeoQuerySet(QuerySet):
u, unit_name, s = get_srid_info(srid, connection)
geodetic = unit_name.lower() in geo_field.geodetic_units
if geodetic and not connection.features.supports_distance_geodetic:
if geodetic and (not connection.features.supports_distance_geodetic or connection.ops.spatialite):
raise ValueError(
'This database does not support linear distance '
'calculations on geodetic coordinate systems.'

4
docs/releases/1.11.txt
View File

@ -149,6 +149,10 @@ Minor features
* Added support for the :lookup:`dwithin` lookup on SpatiaLite.
* The :class:`~django.contrib.gis.db.models.functions.Area` function,
:class:`~django.contrib.gis.db.models.functions.Distance` function, and
distance lookups now work with geodetic coordinates on SpatiaLite.
* The OpenLayers-based form widgets now use ``OpenLayers.js`` from
``https://cdnjs.cloudflare.com`` which is more suitable for production use
than the the old ``http://openlayers.org`` source.

24
tests/gis_tests/distapp/tests.py
View File

@ -1,5 +1,7 @@
from __future__ import unicode_literals
from unittest import skipIf
from django.contrib.gis.db.models.functions import (
Area, Distance, Length, Perimeter, Transform,
)
@ -143,6 +145,7 @@ class DistanceTest(TestCase):
self.assertAlmostEqual(m_distances[i], c.distance.m, tol)
self.assertAlmostEqual(ft_distances[i], c.distance.survey_ft, tol)
@skipIf(spatialite, "distance method doesn't support geodetic coordinates on SpatiaLite.")
@skipUnlessDBFeature("has_distance_method", "supports_distance_geodetic")
@ignore_warnings(category=RemovedInDjango20Warning)
def test_distance_geodetic(self):
@ -270,12 +273,15 @@ class DistanceTest(TestCase):
# a 100km of that line (which should exclude only Hobart & Adelaide).
line = GEOSGeometry('LINESTRING(144.9630 -37.8143,151.2607 -33.8870)', 4326)
dist_qs = AustraliaCity.objects.filter(point__distance_lte=(line, D(km=100)))
self.assertEqual(9, dist_qs.count())
self.assertEqual(['Batemans Bay', 'Canberra', 'Hillsdale',
expected_cities = [
'Batemans Bay', 'Canberra', 'Hillsdale',
'Melbourne', 'Mittagong', 'Shellharbour',
'Sydney', 'Thirroul', 'Wollongong'],
self.get_names(dist_qs))
'Sydney', 'Thirroul', 'Wollongong',
]
if spatialite:
# SpatiaLite is less accurate and returns 102.8km for Batemans Bay.
expected_cities.pop(0)
self.assertEqual(expected_cities, self.get_names(dist_qs))
# Too many params (4 in this case) should raise a ValueError.
queryset = AustraliaCity.objects.filter(point__distance_lte=('POINT(5 23)', D(km=100), 'spheroid', '4'))
@ -355,6 +361,7 @@ class DistanceTest(TestCase):
for i, z in enumerate(SouthTexasZipcode.objects.order_by('name').area()):
self.assertAlmostEqual(area_sq_m[i], z.area.sq_m, tol)
@skipIf(spatialite, "length method doesn't support geodetic coordinates on SpatiaLite.")
@skipUnlessDBFeature("has_length_method")
@ignore_warnings(category=RemovedInDjango20Warning)
def test_length(self):
@ -544,8 +551,9 @@ class DistanceFunctionsTests(TestCase):
40435.4335201384, 0, 68272.3896586844, 12375.0643697706, 0]
qs = AustraliaCity.objects.annotate(distance=Distance('point', ls)).order_by('name')
for city, distance in zip(qs, distances):
# Testing equivalence to within a meter.
self.assertAlmostEqual(distance, city.distance.m, 0)
# Testing equivalence to within a meter (kilometer on SpatiaLite).
tol = -3 if spatialite else 0
self.assertAlmostEqual(distance, city.distance.m, tol)
@skipUnlessDBFeature("has_Distance_function", "supports_distance_geodetic")
def test_distance_geodetic_spheroid(self):
@ -575,7 +583,7 @@ class DistanceFunctionsTests(TestCase):
).order_by('id')
for i, c in enumerate(qs):
self.assertAlmostEqual(spheroid_distances[i], c.distance.m, tol)
if postgis:
if postgis or spatialite:
# PostGIS uses sphere-only distances by default, testing these as well.
qs = AustraliaCity.objects.exclude(id=hillsdale.id).annotate(
distance=Distance('point', hillsdale.point)

26
tests/gis_tests/geogapp/tests.py
View File

@ -4,18 +4,20 @@ Tests for geography support in PostGIS
from __future__ import unicode_literals
import os
from unittest import skipUnless
from unittest import skipIf, skipUnless
from django.contrib.gis.db import models
from django.contrib.gis.db.models.functions import Area, Distance
from django.contrib.gis.measure import D
from django.db import connection
from django.db.models.functions import Cast
from django.test import TestCase, ignore_warnings, skipUnlessDBFeature
from django.test import (
TestCase, ignore_warnings, skipIfDBFeature, skipUnlessDBFeature,
)
from django.utils._os import upath
from django.utils.deprecation import RemovedInDjango20Warning
from ..utils import oracle, postgis
from ..utils import oracle, postgis, spatialite
from .models import City, County, Zipcode
@ -27,6 +29,7 @@ class GeographyTest(TestCase):
"Ensure geography features loaded properly."
self.assertEqual(8, City.objects.count())
@skipIf(spatialite, "SpatiaLite doesn't support distance lookups with Distance objects.")
@skipUnlessDBFeature("supports_distances_lookups", "supports_distance_geodetic")
def test02_distance_lookup(self):
"Testing GeoQuerySet distance lookup support on non-point geography fields."
@ -42,6 +45,7 @@ class GeographyTest(TestCase):
for cities in [cities1, cities2]:
self.assertEqual(['Dallas', 'Houston', 'Oklahoma City'], cities)
@skipIf(spatialite, "distance() doesn't support geodetic coordinates on SpatiaLite.")
@skipUnlessDBFeature("has_distance_method", "supports_distance_geodetic")
@ignore_warnings(category=RemovedInDjango20Warning)
def test03_distance_method(self):
@ -97,6 +101,7 @@ class GeographyTest(TestCase):
self.assertEqual(name, c.name)
self.assertEqual(state, c.state)
@skipIf(spatialite, "area() doesn't support geodetic coordinates on SpatiaLite.")
@skipUnlessDBFeature("has_area_method", "supports_distance_geodetic")
@ignore_warnings(category=RemovedInDjango20Warning)
def test06_geography_area(self):
@ -136,17 +141,22 @@ class GeographyFunctionTests(TestCase):
"""
if oracle:
ref_dists = [0, 4899.68, 8081.30, 9115.15]
elif spatialite:
# SpatiaLite returns non-zero distance for polygons and points
# covered by that polygon.
ref_dists = [326.61, 4899.68, 8081.30, 9115.15]
else:
ref_dists = [0, 4891.20, 8071.64, 9123.95]
htown = City.objects.get(name='Houston')
qs = Zipcode.objects.annotate(distance=Distance('poly', htown.point))
for z, ref in zip(qs, ref_dists):
self.assertAlmostEqual(z.distance.m, ref, 2)
# Distance function in combination with a lookup.
if not spatialite:
# Distance function combined with a lookup.
hzip = Zipcode.objects.get(code='77002')
self.assertEqual(qs.get(distance__lte=0), hzip)
@skipUnlessDBFeature("has_Area_function", "supports_distance_geodetic")
@skipUnlessDBFeature("has_Area_function", "supports_area_geodetic")
def test_geography_area(self):
"""
Testing that Area calculations work on geography columns.
@ -158,3 +168,9 @@ class GeographyFunctionTests(TestCase):
rounded_value = z.area.sq_m
rounded_value -= z.area.sq_m % 1000
self.assertEqual(rounded_value, 5439000)
@skipUnlessDBFeature("has_Area_function")
@skipIfDBFeature("supports_area_geodetic")
def test_geodetic_area_raises_if_not_supported(self):
with self.assertRaisesMessage(NotImplementedError, 'Area on geodetic coordinate systems not supported.'):
Zipcode.objects.annotate(area=Area('poly')).get(code='77002')