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Fixed the `add_postgis_srs` routine to support SpatiaLite. 

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10229 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Justin Bronn 2009-03-30 22:54:24 +00:00
parent 13ea4a9133
commit a1e7723c79
1 changed files with 32 additions and 10 deletions
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42
django/contrib/gis/utils/srs.py
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@ -1,27 +1,49 @@
def add_postgis_srs(srs):
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
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.
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(
srid=srs.srid, auth_name='EPSG', auth_srid=srs.srid,
srtext=srs.wkt, proj4text=srs.proj4)
sr, created = SpatialRefSys.objects.get_or_create(**kwargs)