Merge pull request #72 from jensb/master

Update *_distance_sql to work with customized latitude and longitude attribute names

lib/geokit-rails/acts_as_mappable.rb

@@ -315,22 +315,33 @@ def substitute_distance_in_where_values(arel, origin, units=default_units, formu
       # Returns the distance SQL using the spherical world formula (Haversine).  The SQL is tuned
       # to the database in use.
       def sphere_distance_sql(origin, units)
-        lat = deg2rad(origin.lat)
-        lng = deg2rad(origin.lng)
+        # "origin" can be a Geokit::LatLng (with :lat and :lng methods), e.g.
+        # when using geo_scope or it can be an ActsAsMappable with customized
+        # latitude and longitude methods, e.g. when using distance_sql.
+        lat = deg2rad(get_lat(origin))
+        lng = deg2rad(get_lng(origin))
         multiplier = units_sphere_multiplier(units)
-
         adapter.sphere_distance_sql(lat, lng, multiplier) if adapter
       end
 
       # Returns the distance SQL using the flat-world formula (Phythagorean Theory).  The SQL is tuned
       # to the database in use.
       def flat_distance_sql(origin, units)
         lat_degree_units = units_per_latitude_degree(units)
-        lng_degree_units = units_per_longitude_degree(origin.lat, units)
-
+        lng_degree_units = units_per_longitude_degree(get_lat(origin), units)
         adapter.flat_distance_sql(origin, lat_degree_units, lng_degree_units)
       end
 
+      def get_lat(origin)
+        origin.respond_to?(:lat) ? origin.lat \
+                                 : origin.send(:"#{lat_column_name}")
+      end
+
+      def get_lng(origin)
+        origin.respond_to?(:lng) ? origin.lng \
+                                 : origin.send(:"#{lng_column_name}")
+      end
+
     end # ClassMethods
 
     # this is the callback for auto_geocoding
@@ -339,8 +350,8 @@ def auto_geocode_address
       geo=Geokit::Geocoders::MultiGeocoder.geocode(address)
 
       if geo.success
-        self.send("#{lat_column_name}=", geo.lat)
-        self.send("#{lng_column_name}=", geo.lng)
+        self.send("#{lat_column_name}=", geo.send(:"#{lat_column_name}"))
+        self.send("#{lng_column_name}=", geo.send(:"#{lng_column_name}"))
       else
         errors.add(auto_geocode_field, auto_geocode_error_message)
       end