diff -r 000000000000 -r 0d40e90630ef web/lib/django/contrib/gis/utils/srs.py --- /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)