app/django/contrib/gis/db/backend/postgis/models.py
author Lennard de Rijk <ljvderijk@gmail.com>
Sat, 11 Jul 2009 23:15:22 +0200
changeset 2594 dd300af0e7df
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Added empty Tasks package and queue.yaml. Also reserved an admin only URL space for use by Tasks.

"""
 The GeometryColumns and SpatialRefSys models for the PostGIS backend.
"""
from django.db import models
from django.contrib.gis.models import SpatialRefSysMixin

# Checking for the presence of GDAL (needed for the SpatialReference object)
from django.contrib.gis.gdal import HAS_GDAL
if HAS_GDAL:
    from django.contrib.gis.gdal import SpatialReference

class GeometryColumns(models.Model):
    """
    The 'geometry_columns' table from the PostGIS. See the PostGIS
    documentation at Ch. 4.2.2.
    """
    f_table_catalog = models.CharField(max_length=256)
    f_table_schema = models.CharField(max_length=256)
    f_table_name = models.CharField(max_length=256)
    f_geometry_column = models.CharField(max_length=256)
    coord_dimension = models.IntegerField()
    srid = models.IntegerField(primary_key=True)
    type = models.CharField(max_length=30)

    class Meta:
        db_table = 'geometry_columns'

    @classmethod
    def table_name_col(cls):
        """
        Returns the name of the metadata column used to store the 
        the feature table name.
        """
        return 'f_table_name'

    @classmethod
    def geom_col_name(cls):
        """
        Returns the name of the metadata column used to store the 
        the feature geometry column.
        """
        return 'f_geometry_column'

    def __unicode__(self):
        return "%s.%s - %dD %s field (SRID: %d)" % \
               (self.f_table_name, self.f_geometry_column,
                self.coord_dimension, self.type, self.srid)

class SpatialRefSys(models.Model, SpatialRefSysMixin):
    """
    The 'spatial_ref_sys' table from PostGIS. See the PostGIS
    documentaiton at Ch. 4.2.1.
    """
    srid = models.IntegerField(primary_key=True)
    auth_name = models.CharField(max_length=256)
    auth_srid = models.IntegerField()
    srtext = models.CharField(max_length=2048)
    proj4text = models.CharField(max_length=2048)

    class Meta:
        db_table = 'spatial_ref_sys'

    @property
    def wkt(self):
        return self.srtext

    @classmethod
    def wkt_col(cls):
        return 'srtext'