app/django/contrib/gis/utils/srs.py
author Sverre Rabbelier <srabbelier@gmail.com>
Fri, 06 Mar 2009 17:12:51 +0000
changeset 1688 f8457a410d1f
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permissions -rw-r--r--
Split out test_model model and logic into it's own module Patch by: Sverre Rabbelier
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def add_postgis_srs(srs):
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    """
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    This function takes a GDAL SpatialReference system and adds its
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    information to the PostGIS `spatial_ref_sys` table -- enabling
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    spatial transformations with PostGIS.  This is handy for adding
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    spatial reference systems not included by default with PostGIS.  
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    For example, the following adds the so-called "Google Maps Mercator 
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    Projection" (available in GDAL 1.5):
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    >>> add_postgis_srs(SpatialReference(900913))
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    Note: By default, the `auth_name` is set to 'EPSG' -- this should
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    probably be changed.
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    """
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    from django.contrib.gis.models import SpatialRefSys
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    from django.contrib.gis.gdal import SpatialReference
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    if not isinstance(srs, SpatialReference):
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        srs = SpatialReference(srs)
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    if srs.srid is None:
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        raise Exception('Spatial reference requires an SRID to be compatible with PostGIS.')
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    # Creating the spatial_ref_sys model.
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    sr, created = SpatialRefSys.objects.get_or_create(
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        srid=srs.srid, auth_name='EPSG', auth_srid=srs.srid, 
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        srtext=srs.wkt, proj4text=srs.proj4)