--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/contrib/gis/utils/srs.py	Wed Jan 20 00:34:04 2010 +0100
@@ -0,0 +1,49 @@
+def add_postgis_srs(srs, auth_name='EPSG', auth_srid=None, ref_sys_name=None):
+    """
+    This function takes a GDAL SpatialReference system and adds its
+    information to the PostGIS `spatial_ref_sys` table -- enabling
+    spatial transformations with PostGIS.  This is handy for adding
+    spatial reference systems not included by default with PostGIS.
+    For example, the following adds the so-called "Google Maps Mercator
+    Projection" (available in GDAL 1.5):
+
+    >>> add_postgis_srs(SpatialReference(900913))
+
+    Keyword Arguments:
+     auth_name: This keyword may be customized with the value of the
+                `auth_name` field.  Defaults to 'EPSG'.
+
+     auth_srid: This keyword may be customized with the value of the
+                `auth_srid` field.  Defaults to the SRID determined
+                by GDAL.
+
+     ref_sys_name: For SpatiaLite users only, sets the value of the
+                   the `ref_sys_name` field.  Defaults to the name
+                   determined by GDAL.
+    """
+    from django.contrib.gis.db.backend import SpatialBackend
+    from django.contrib.gis.models import SpatialRefSys
+    from django.contrib.gis.gdal import SpatialReference
+
+    if SpatialBackend.oracle or SpatialBackend.mysql:
+        raise Exception('This utility not supported on Oracle or MySQL spatial backends.')
+
+    if not isinstance(srs, SpatialReference):
+        srs = SpatialReference(srs)
+
+    if srs.srid is None:
+        raise Exception('Spatial reference requires an SRID to be compatible with PostGIS.')
+
+    # Initializing the keyword arguments dictionary for both PostGIS and SpatiaLite.
+    kwargs = {'srid' : srs.srid,
+              'auth_name' : auth_name,
+              'auth_srid' : auth_srid or srs.srid,
+              'proj4text' : srs.proj4,
+              }
+
+    # Backend-specific keyword settings.
+    if SpatialBackend.postgis: kwargs['srtext'] = srs.wkt
+    if SpatialBackend.spatialite: kwargs['ref_sys_name'] = ref_sys_name or srs.name
+
+    # Creating the spatial_ref_sys model.
+    sr, created = SpatialRefSys.objects.get_or_create(**kwargs)