author | Sverre Rabbelier <srabbelier@gmail.com> |
Sat, 21 Feb 2009 21:56:55 +0000 | |
changeset 1446 | bcbbcb72429d |
parent 323 | ff1a9aa48cfd |
permissions | -rw-r--r-- |
323
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
1 |
def add_postgis_srs(srs): |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
2 |
""" |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
3 |
This function takes a GDAL SpatialReference system and adds its |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
4 |
information to the PostGIS `spatial_ref_sys` table -- enabling |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
5 |
spatial transformations with PostGIS. This is handy for adding |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
6 |
spatial reference systems not included by default with PostGIS. |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
7 |
For example, the following adds the so-called "Google Maps Mercator |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
8 |
Projection" (available in GDAL 1.5): |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
9 |
|
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
10 |
>>> add_postgis_srs(SpatialReference(900913)) |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
11 |
|
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
12 |
Note: By default, the `auth_name` is set to 'EPSG' -- this should |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
13 |
probably be changed. |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
14 |
""" |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
15 |
from django.contrib.gis.models import SpatialRefSys |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
16 |
from django.contrib.gis.gdal import SpatialReference |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
17 |
|
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
18 |
if not isinstance(srs, SpatialReference): |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
19 |
srs = SpatialReference(srs) |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
20 |
|
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
21 |
if srs.srid is None: |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
22 |
raise Exception('Spatial reference requires an SRID to be compatible with PostGIS.') |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
23 |
|
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
24 |
# Creating the spatial_ref_sys model. |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
25 |
sr, created = SpatialRefSys.objects.get_or_create( |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
26 |
srid=srs.srid, auth_name='EPSG', auth_srid=srs.srid, |
ff1a9aa48cfd
Load ../vendor/django into trunk/app/django.
Pawel Solyga <Pawel.Solyga@gmail.com>
parents:
diff
changeset
|
27 |
srtext=srs.wkt, proj4text=srs.proj4) |