initial geodjango implementation

location/models.py

@@ -1,8 +1,10 @@
+from django.contrib.gis.db import models as gis_models
 from django.db import models
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.core.validators import MinValueValidator, MaxValueValidator
 from simple_history.models import HistoricalRecords
+from django.contrib.gis.geos import Point
 
 class Location(models.Model):
     """
@@ -27,7 +29,7 @@ class Location(models.Model):
             MinValueValidator(-90),
             MaxValueValidator(90)
         ],
-        help_text="Latitude coordinate",
+        help_text="Latitude coordinate (legacy field)",
         null=True,
         blank=True
     )
@@ -38,12 +40,20 @@ class Location(models.Model):
             MinValueValidator(-180),
             MaxValueValidator(180)
         ],
-        help_text="Longitude coordinate",
+        help_text="Longitude coordinate (legacy field)",
         null=True,
         blank=True
     )
     
-    # Address components - all made nullable
+    # GeoDjango point field
+    point = gis_models.PointField(
+        srid=4326,  # WGS84 coordinate system
+        null=True,
+        blank=True,
+        help_text="Geographic coordinates as a Point"
+    )
+    
+    # Address components
     street_address = models.CharField(max_length=255, blank=True, null=True)
     city = models.CharField(max_length=100, blank=True, null=True)
     state = models.CharField(max_length=100, blank=True, null=True, help_text="State/Region/Province")
@@ -58,7 +68,6 @@ class Location(models.Model):
     class Meta:
         indexes = [
             models.Index(fields=['content_type', 'object_id']),
-            models.Index(fields=['latitude', 'longitude']),
             models.Index(fields=['city']),
             models.Index(fields=['country']),
         ]
@@ -73,6 +82,15 @@ class Location(models.Model):
         location_str = ", ".join(location_parts) if location_parts else "Unknown location"
         return f"{self.name} ({location_str})"
 
+    def save(self, *args, **kwargs):
+        # Sync point field with lat/lon fields for backward compatibility
+        if self.latitude is not None and self.longitude is not None and not self.point:
+            self.point = Point(float(self.longitude), float(self.latitude))
+        elif self.point and (self.latitude is None or self.longitude is None):
+            self.longitude = self.point.x
+            self.latitude = self.point.y
+        super().save(*args, **kwargs)
+
     def get_formatted_address(self):
         """Returns a formatted address string"""
         components = []
@@ -91,6 +109,29 @@ class Location(models.Model):
     @property
     def coordinates(self):
         """Returns coordinates as a tuple"""
-        if self.latitude is not None and self.longitude is not None:
+        if self.point:
+            return (self.point.y, self.point.x)  # Returns (latitude, longitude)
+        elif self.latitude is not None and self.longitude is not None:
             return (float(self.latitude), float(self.longitude))
         return None
+
+    def distance_to(self, other_location):
+        """
+        Calculate the distance to another location in meters.
+        Returns None if either location is missing coordinates.
+        """
+        if not self.point or not other_location.point:
+            return None
+        return self.point.distance(other_location.point) * 100000  # Convert to meters
+
+    def nearby_locations(self, distance_km=10):
+        """
+        Find locations within specified distance in kilometers.
+        Returns a queryset of nearby Location objects.
+        """
+        if not self.point:
+            return Location.objects.none()
+        
+        return Location.objects.filter(
+            point__distance_lte=(self.point, distance_km * 1000)  # Convert km to meters
+        ).exclude(pk=self.pk)