28 lines
1.1 KiB
Python
28 lines
1.1 KiB
Python
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)
|