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gis: Added the extent method to GeoQuerySet; moved various spatial-backend settings into the SpatialBackend container class.
git-svn-id: http://code.djangoproject.com/svn/django/branches/gis@7028 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Justin Bronn
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398eca3fb2
@ -5,17 +5,14 @@
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needed for GeoDjango.
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(1) GeoBackEndField, a base class needed for GeometryField.
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(2) GeometryProxy, for lazy-instantiated geometries from the
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database output.
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(3) GIS_TERMS, a list of acceptable geographic lookup types for
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(2) GIS_TERMS, a list of acceptable geographic lookup types for
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the backend.
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(4) The `parse_lookup` function, used for spatial SQL construction by
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(3) The `parse_lookup` function, used for spatial SQL construction by
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the GeoQuerySet.
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(5) The `create_spatial_db`, and `get_geo_where_clause`
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(4) The `create_spatial_db`, and `get_geo_where_clause`
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routines (needed by `parse_lookup`).
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Currently only PostGIS is supported, but someday backends will be added for
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additional spatial databases (e.g., Oracle, DB2).
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(5) The `SpatialBackend` object, which contains information specific
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to the spatial backend.
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"""
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from types import StringType, UnicodeType
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from django.conf import settings
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@ -26,7 +23,7 @@ from django.utils.datastructures import SortedDict
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from django.contrib.gis.geos import GEOSGeometry
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# These routines (needed by GeoManager), default to False.
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ASGML, ASKML, DISTANCE, TRANSFORM, UNION, VERSION = (False, False, False, False, False, False)
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ASGML, ASKML, DISTANCE, EXTENT, TRANSFORM, UNION, VERSION = (False, False, False, False, False, False, False)
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if settings.DATABASE_ENGINE == 'postgresql_psycopg2':
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# PostGIS is the spatial database, getting the rquired modules,
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@ -34,7 +31,7 @@ if settings.DATABASE_ENGINE == 'postgresql_psycopg2':
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from django.contrib.gis.db.backend.postgis import \
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PostGISField as GeoBackendField, POSTGIS_TERMS as GIS_TERMS, \
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create_spatial_db, get_geo_where_clause, \
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ASGML, ASKML, DISTANCE, GEOM_SELECT, TRANSFORM, UNION, \
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ASGML, ASKML, DISTANCE, EXTENT, GEOM_SELECT, TRANSFORM, UNION, \
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MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2
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VERSION = (MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2)
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SPATIAL_BACKEND = 'postgis'
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@ -55,6 +52,18 @@ elif settings.DATABASE_ENGINE == 'mysql':
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else:
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raise NotImplementedError('No Geographic Backend exists for %s' % settings.DATABASE_ENGINE)
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class SpatialBackend(object):
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"A container for properties of the Spatial Backend."
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as_kml = ASKML
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as_gml = ASGML
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distance = DISTANCE
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extent = EXTENT
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name = SPATIAL_BACKEND
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select = GEOM_SELECT
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transform = TRANSFORM
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union = UNION
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version = VERSION
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#### query.py overloaded functions ####
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# parse_lookup() and lookup_inner() are modified from their django/db/models/query.py
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# counterparts to support constructing SQL for geographic queries.
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@ -6,4 +6,4 @@ from django.contrib.gis.db.backend.postgis.field import PostGISField, gqn
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from django.contrib.gis.db.backend.postgis.query import \
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get_geo_where_clause, GEOM_FUNC_PREFIX, POSTGIS_TERMS, \
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MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2, \
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ASKML, ASGML, DISTANCE, GEOM_FROM_TEXT, UNION, TRANSFORM, GEOM_SELECT
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ASKML, ASGML, DISTANCE, EXTENT, GEOM_FROM_TEXT, UNION, TRANSFORM, GEOM_SELECT
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@ -40,6 +40,7 @@ if MAJOR_VERSION >= 1:
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ASKML = get_func('AsKML')
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ASGML = get_func('AsGML')
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DISTANCE = get_func('Distance')
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EXTENT = get_func('extent')
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GEOM_FROM_TEXT = get_func('GeomFromText')
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GEOM_FROM_WKB = get_func('GeomFromWKB')
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TRANSFORM = get_func('Transform')
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@ -10,6 +10,9 @@ class GeoManager(Manager):
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def distance(self, *args, **kwargs):
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return self.get_query_set().distance(*args, **kwargs)
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def extent(self, *args, **kwargs):
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return self.get_query_set().extent(*args, **kwargs)
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def gml(self, *args, **kwargs):
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return self.get_query_set().gml(*args, **kwargs)
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@ -6,13 +6,12 @@ from django.db.models.fields import FieldDoesNotExist
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from django.utils.datastructures import SortedDict
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from django.contrib.gis.db.models.fields import GeometryField
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# parse_lookup depends on the spatial database backend.
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from django.contrib.gis.db.backend import parse_lookup, \
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ASGML, ASKML, DISTANCE, GEOM_SELECT, SPATIAL_BACKEND, TRANSFORM, UNION, VERSION
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from django.contrib.gis.db.backend import parse_lookup, SpatialBackend
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from django.contrib.gis.geos import GEOSGeometry
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# Shortcut booleans for determining the backend.
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oracle = SPATIAL_BACKEND == 'oracle'
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postgis = SPATIAL_BACKEND == 'postgis'
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oracle = SpatialBackend.name == 'oracle'
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postgis = SpatialBackend.name == 'postgis'
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class GeoQ(Q):
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"Geographical query encapsulation object."
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@ -37,10 +36,10 @@ class GeoQuerySet(QuerySet):
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# If GEOM_SELECT is defined in the backend, then it will be used
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# for the selection format of the geometry column.
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if GEOM_SELECT:
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if SpatialBackend.select:
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# Transformed geometries in Oracle use EWKT so that the SRID
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# on the transformed lazy geometries is set correctly).
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self._geo_fmt = GEOM_SELECT
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self._geo_fmt = SpatialBackend.select
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else:
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self._geo_fmt = '%s'
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@ -259,6 +258,7 @@ class GeoQuerySet(QuerySet):
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given geometry in a `distance` attribute on each element of the
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GeoQuerySet.
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"""
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DISTANCE = SpatialBackend.distance
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if not DISTANCE:
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raise ImproperlyConfigured('Distance() stored proecedure not available.')
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@ -299,12 +299,55 @@ class GeoQuerySet(QuerySet):
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dist_select = {'distance' : '%s(%s, %s)' % (DISTANCE, field_col, geom_sql)}
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return self.extra(select=dist_select)
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def extent(self, field_name=None):
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"""
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Returns the extent (aggregate) of the features in the GeoQuerySet. The
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extent will be returned as a 4-tuple, consisting of (xmin, ymin, xmax, ymax).
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"""
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EXTENT = SpatialBackend.extent
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if not EXTENT:
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raise ImproperlyConfigured('Extent stored procedure not available.')
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if not field_name:
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field_name = self._get_geofield()
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field_col = self._geo_column(field_name)
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if not field_col:
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raise TypeError('Extent information only available on GeometryFields.')
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# Getting the SQL for the query.
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try:
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select, sql, params = self._get_sql_clause()
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except EmptyResultSet:
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return None
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# Constructing the query that will select the extent.
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extent_sql = ('SELECT %s(%s)' % (EXTENT, field_col)) + sql
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# Getting a cursor, executing the query, and extracting the returned
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# value from the extent function.
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cursor = connection.cursor()
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cursor.execute(extent_sql, params)
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box = cursor.fetchone()[0]
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if box:
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# TODO: Parsing of BOX3D, Oracle support (patches welcome!)
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# Box text will be something like "BOX(-90.0 30.0, -85.0 40.0)";
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# parsing out and returning as a 4-tuple.
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ll, ur = box[4:-1].split(',')
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xmin, ymin = map(float, ll.split())
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xmax, ymax = map(float, ur.split())
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return (xmin, ymin, xmax, ymax)
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else:
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return None
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def gml(self, field_name=None, precision=8, version=2):
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"""
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Returns GML representation of the given field in a `gml` attribute
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on each element of the GeoQuerySet.
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"""
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# Is GML output supported?
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ASGML = SpatialBackend.as_gml
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if not ASGML:
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raise ImproperlyConfigured('AsGML() stored procedure not available.')
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@ -322,7 +365,7 @@ class GeoQuerySet(QuerySet):
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elif postgis:
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# PostGIS AsGML() aggregate function parameter order depends on the
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# version -- uggh.
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major, minor1, minor2 = VERSION
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major, minor1, minor2 = SpatialBackend.version
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if major >= 1 and (minor1 > 3 or (minor1 == 3 and minor2 > 1)):
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gml_select = {'gml':'%s(%s,%s,%s)' % (ASGML, version, field_col, precision)}
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else:
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@ -337,6 +380,7 @@ class GeoQuerySet(QuerySet):
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attribute on each element of the GeoQuerySet.
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"""
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# Is KML output supported?
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ASKML = SpatialBackend.as_kml
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if not ASKML:
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raise ImproperlyConfigured('AsKML() stored procedure not available.')
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@ -375,6 +419,7 @@ class GeoQuerySet(QuerySet):
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# Setting the key for the field's column with the custom SELECT SQL to
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# override the geometry column returned from the database.
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TRANSFORM = SpatialBackend.transform
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if oracle:
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custom_sel = '%s(%s, %s)' % (TRANSFORM, col, srid)
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self._ewkt = srid
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@ -391,6 +436,7 @@ class GeoQuerySet(QuerySet):
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Oracle backends only.
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"""
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# Making sure backend supports the Union stored procedure
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UNION = SpatialBackend.union
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if not UNION:
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raise ImproperlyConfigured('Union stored procedure not available.')
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@ -172,6 +172,20 @@ class GeoModelTest(unittest.TestCase):
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self.assertAlmostEqual(ptown.x, p.point.x, prec)
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self.assertAlmostEqual(ptown.y, p.point.y, prec)
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@no_oracle # Most likely can do this in Oracle, however, it is not yet implemented (patches welcome!)
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def test05_extent(self):
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"Testing the extent() GeoManager method."
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# Reference query:
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# `SELECT ST_extent(point) FROM geoapp_city WHERE (name='Houston' or name='Dallas');`
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# => BOX(-96.8016128540039 29.7633724212646,-95.3631439208984 32.7820587158203)
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expected = (-96.8016128540039, 29.7633724212646, -95.3631439208984, 32.782058715820)
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qs = City.objects.filter(name__in=('Houston', 'Dallas'))
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extent = qs.extent()
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for val, exp in zip(extent, expected):
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self.assertAlmostEqual(exp, val, 8)
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def test09_disjoint(self):
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"Testing the `disjoint` lookup type."
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if DISABLE: return
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@ -112,7 +112,7 @@ from datetime import date, datetime
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from decimal import Decimal
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from django.core.exceptions import ObjectDoesNotExist
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from django.contrib.gis.db.models.fields import GeometryField
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from django.contrib.gis.db.backend import SPATIAL_BACKEND
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from django.contrib.gis.db.backend import SpatialBackend
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from django.contrib.gis.gdal import CoordTransform, DataSource, \
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OGRException, OGRGeometry, OGRGeomType, SpatialReference
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from django.contrib.gis.gdal.field import \
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@ -506,7 +506,7 @@ class LayerMapping(object):
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# Getting the GeometryColumn object.
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try:
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db_table = self.model._meta.db_table
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if SPATIAL_BACKEND == 'oracle': db_table = db_table.upper()
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if SpatialBackend.name == 'oracle': db_table = db_table.upper()
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gc_kwargs = {GeometryColumns.table_name_col() : db_table}
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return GeometryColumns.objects.get(**gc_kwargs)
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except Exception, msg:
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