text: from django.contrib.gis.db import models
  
  class SouthTexasCity(models.Model):
      "City model on projected coordinate system for South Texas."
      name = models.CharField(max_length=30)
      point = models.PointField(srid=32140)
      objects = models.GeoManager()
      def __unicode__(self): return self.name
  
  class SouthTexasCityFt(models.Model):
      "Same City model as above, but U.S. survey feet are the units."
      name = models.CharField(max_length=30)
      point = models.PointField(srid=2278)
      objects = models.GeoManager()
      def __unicode__(self): return self.name
  
  class AustraliaCity(models.Model):
      "City model for Australia, using WGS84."
      name = models.CharField(max_length=30)
      point = models.PointField()
      objects = models.GeoManager()
      def __unicode__(self): return self.name
  
  class CensusZipcode(models.Model):
      "Model for a few South Texas ZIP codes (in original Census NAD83)."
      name = models.CharField(max_length=5)
      poly = models.PolygonField(srid=4269)
      objects = models.GeoManager()
  
  class SouthTexasZipcode(models.Model):
      "Model for a few South Texas ZIP codes."
      name = models.CharField(max_length=5)
      poly = models.PolygonField(srid=32140)
      objects = models.GeoManager()
      def __unicode__(self): return self.name
  
  class Interstate(models.Model):
      "Geodetic model for U.S. Interstates."
      name = models.CharField(max_length=10)
      path = models.LineStringField()
      objects = models.GeoManager()
      def __unicode__(self): return self.name
  
  class SouthTexasInterstate(models.Model):
      "Projected model for South Texas Interstates."
      name = models.CharField(max_length=10)
      path = models.LineStringField(srid=32140)
      objects = models.GeoManager()
      def __unicode__(self): return self.name
  