Changeset 7028

Timestamp:

01/21/08 19:22:27 (6 months ago)

Author:

jbronn

Message:

gis: Added the extent method to GeoQuerySet; moved various spatial-backend settings into the SpatialBackend container class.

Files:

• django/branches/gis/django/contrib/gis/db/backend/__init__.py (modified) (4 diffs)
• django/branches/gis/django/contrib/gis/db/backend/postgis/__init__.py (modified) (1 diff)
• django/branches/gis/django/contrib/gis/db/backend/postgis/query.py (modified) (1 diff)
• django/branches/gis/django/contrib/gis/db/models/manager.py (modified) (1 diff)
• django/branches/gis/django/contrib/gis/db/models/query.py (modified) (10 diffs)
• django/branches/gis/django/contrib/gis/tests/geoapp/tests.py (modified) (1 diff)
• django/branches/gis/django/contrib/gis/utils/layermapping.py (modified) (2 diffs)

django/branches/gis/django/contrib/gis/db/backend/__init__.py

@@ -6 +6 @@
- 
- (1) GeoBackEndField, a base class needed for GeometryField.
-
-
-
+
-     the backend.
-4
+3
-     the GeoQuerySet.
-5
+4
-     routines (needed by `parse_lookup`).
-
-
-
+
+
-"""
-from types import StringType, UnicodeType
@@ -27 +24 @@
-
-# These routines (needed by GeoManager), default to False.
-TRANSFORM, UNION, VERSION = (
+EXTENT, TRANSFORM, UNION, VERSION = (False, 
-
-if settings.DATABASE_ENGINE == 'postgresql_psycopg2':
@@ -35 +32 @@
-        PostGISField as GeoBackendField, POSTGIS_TERMS as GIS_TERMS, \
-        create_spatial_db, get_geo_where_clause, \
-
+EXTENT, 
-        MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2
-    VERSION = (MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2)
@@ -55 +52 @@
-else:
-    raise NotImplementedError('No Geographic Backend exists for %s' % settings.DATABASE_ENGINE)
+
+class SpatialBackend(object):
+    "A container for properties of the Spatial Backend."
+    as_kml = ASKML
+    as_gml = ASGML
+    distance = DISTANCE
+    extent = EXTENT
+    name = SPATIAL_BACKEND
+    select = GEOM_SELECT
+    transform = TRANSFORM
+    union = UNION
+    version = VERSION
-
-####    query.py overloaded functions    ####

django/branches/gis/django/contrib/gis/db/backend/postgis/__init__.py

@@ -7 +7 @@
-    get_geo_where_clause, GEOM_FUNC_PREFIX, POSTGIS_TERMS, \
-    MAJOR_VERSION, MINOR_VERSION1, MINOR_VERSION2, \
-
+EXTENT, 

django/branches/gis/django/contrib/gis/db/backend/postgis/query.py

@@ -41 +41 @@
-    ASGML = get_func('AsGML')
-    DISTANCE = get_func('Distance')
+    EXTENT = get_func('extent')
-    GEOM_FROM_TEXT = get_func('GeomFromText')
-    GEOM_FROM_WKB = get_func('GeomFromWKB')

django/branches/gis/django/contrib/gis/db/models/manager.py

@@ -11 +11 @@
-        return self.get_query_set().distance(*args, **kwargs)
-
+    def extent(self, *args, **kwargs):
+        return self.get_query_set().extent(*args, **kwargs)
+
-    def gml(self, *args, **kwargs):
-        return self.get_query_set().gml(*args, **kwargs)

django/branches/gis/django/contrib/gis/db/models/query.py

@@ -7 +7 @@
-from django.contrib.gis.db.models.fields import GeometryField
-# parse_lookup depends on the spatial database backend.
-
-
+
-from django.contrib.gis.geos import GEOSGeometry
-
-# Shortcut booleans for determining the backend.
-= SPATIAL_BACKEND
-PATIAL_BACKEND
+ = SpatialBackend.name
+patialBackend.name
-
-class GeoQ(Q):
@@ -24 +23 @@
-class GeoQuerySet(QuerySet):
-    "Geographical-enabled QuerySet object."
-
+    
-    #### Overloaded QuerySet Routines ####
-    def __init__(self, model=None):
@@ -38 +37 @@
-        # If GEOM_SELECT is defined in the backend, then it will be used
-        # for the selection format of the geometry column.
-GEOM_SELECT
+SpatialBackend.select
-            # Transformed geometries in Oracle use EWKT so that the SRID
-            # on the transformed lazy geometries is set correctly).
-GEOM_SELECT
+SpatialBackend.select
-        else:
-            self._geo_fmt = '%s'
@@ -260 +259 @@
-        GeoQuerySet.
-        """
+        DISTANCE = SpatialBackend.distance
-        if not DISTANCE:
-            raise ImproperlyConfigured('Distance() stored proecedure not available.')
@@ -300 +300 @@
-        return self.extra(select=dist_select)
-
+    def extent(self, field_name=None):
+        """
+        Returns the extent (aggregate) of the features in the GeoQuerySet.  The
+        extent will be returned as a 4-tuple, consisting of (xmin, ymin, xmax, ymax).
+        """
+        EXTENT = SpatialBackend.extent
+        if not EXTENT:
+            raise ImproperlyConfigured('Extent stored procedure not available.')
+
+        if not field_name:
+            field_name = self._get_geofield()
+
+        field_col = self._geo_column(field_name)
+        if not field_col:
+            raise TypeError('Extent information only available on GeometryFields.')
+
+        # Getting the SQL for the query.
+        try:
+            select, sql, params = self._get_sql_clause()
+        except EmptyResultSet:
+            return None
+        
+        # Constructing the query that will select the extent.
+        extent_sql = ('SELECT %s(%s)' % (EXTENT, field_col)) + sql
+
+        # Getting a cursor, executing the query, and extracting the returned
+        # value from the extent function.
+        cursor = connection.cursor()
+        cursor.execute(extent_sql, params)
+        box = cursor.fetchone()[0]
+
+        if box: 
+            # TODO: Parsing of BOX3D, Oracle support (patches welcome!)
+            #  Box text will be something like "BOX(-90.0 30.0, -85.0 40.0)"; 
+            #  parsing out and returning as a 4-tuple.
+            ll, ur = box[4:-1].split(',')
+            xmin, ymin = map(float, ll.split())
+            xmax, ymax = map(float, ur.split())
+            return (xmin, ymin, xmax, ymax)
+        else: 
+            return None
+
-    def gml(self, field_name=None, precision=8, version=2):
-        """
@@ -306 +348 @@
-        """
-        # Is GML output supported?
+        ASGML = SpatialBackend.as_gml
-        if not ASGML:
-            raise ImproperlyConfigured('AsGML() stored procedure not available.')
@@ -323 +366 @@
-            # PostGIS AsGML() aggregate function parameter order depends on the
-            # version -- uggh.
-VERSION
+SpatialBackend.version
-            if major >= 1 and (minor1 > 3 or (minor1 == 3 and minor2 > 1)):
-                gml_select = {'gml':'%s(%s,%s,%s)' % (ASGML, version, field_col, precision)}
@@ -338 +381 @@
-        """
-        # Is KML output supported?
+        ASKML = SpatialBackend.as_kml
-        if not ASKML:
-            raise ImproperlyConfigured('AsKML() stored procedure not available.')
@@ -376 +420 @@
-        # Setting the key for the field's column with the custom SELECT SQL to 
-        # override the geometry column returned from the database.
+        TRANSFORM = SpatialBackend.transform
-        if oracle:
-            custom_sel = '%s(%s, %s)' % (TRANSFORM, col, srid)
@@ -392 +437 @@
-        """
-        # Making sure backend supports the Union stored procedure
+        UNION = SpatialBackend.union
-        if not UNION:
-            raise ImproperlyConfigured('Union stored procedure not available.')

django/branches/gis/django/contrib/gis/tests/geoapp/tests.py

@@ -172 +172 @@
-            self.assertAlmostEqual(ptown.x, p.point.x, prec)
-            self.assertAlmostEqual(ptown.y, p.point.y, prec)
+
+    @no_oracle # Most likely can do this in Oracle, however, it is not yet implemented (patches welcome!)
+    def test05_extent(self):
+        "Testing the extent() GeoManager method."
+        # Reference query:
+        # `SELECT ST_extent(point) FROM geoapp_city WHERE (name='Houston' or name='Dallas');`
+        #   =>  BOX(-96.8016128540039 29.7633724212646,-95.3631439208984 32.7820587158203)
+        expected = (-96.8016128540039, 29.7633724212646, -95.3631439208984, 32.782058715820)
+
+        qs = City.objects.filter(name__in=('Houston', 'Dallas'))
+        extent = qs.extent()
+
+        for val, exp in zip(extent, expected):
+            self.assertAlmostEqual(exp, val, 8)
-
-    def test09_disjoint(self):

django/branches/gis/django/contrib/gis/utils/layermapping.py

@@ -113 +113 @@
-from django.core.exceptions import ObjectDoesNotExist
-from django.contrib.gis.db.models.fields import GeometryField
-PATIAL_BACKEND
+patialBackend
-from django.contrib.gis.gdal import CoordTransform, DataSource, \
-    OGRException, OGRGeometry, OGRGeomType, SpatialReference
@@ -507 +507 @@
-        try:
-            db_table = self.model._meta.db_table
-PATIAL_BACKEND
+patialBackend.name
-            gc_kwargs = {GeometryColumns.table_name_col() : db_table}
-            return GeometryColumns.objects.get(**gc_kwargs)