app/django/contrib/gis/utils/srs.py
author Sverre Rabbelier <srabbelier@gmail.com>
Mon, 03 Nov 2008 19:47:02 +0000
changeset 439 0658c3c9a9dc
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Minor fixes needed for generic key name We no longer try to retreive an entity when there are unset fields. This sort of makes 'getIfFields' obsolete, since we check if fields now anyway. This is needed because getKeyFieldsFromDict expects the fields to be set. Also a minor fix in a Django template so that the generic 'edit' page has a working delete button again.

def add_postgis_srs(srs):
    """
    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))

    Note: By default, the `auth_name` is set to 'EPSG' -- this should
    probably be changed.
    """
    from django.contrib.gis.models import SpatialRefSys
    from django.contrib.gis.gdal import SpatialReference

    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.')
   
    # Creating the spatial_ref_sys model.
    sr, created = SpatialRefSys.objects.get_or_create(
        srid=srs.srid, auth_name='EPSG', auth_srid=srs.srid, 
        srtext=srs.wkt, proj4text=srs.proj4)