Adds the postgis adapter

geokit · Jan 19, 2017 · b6854d4 · b6854d4
1 parent 2a5dc8b
commit b6854d4
Showing 1 changed file with 22 additions and 0 deletions.
diff --git a/lib/geokit-rails/adapters/postgis.rb b/lib/geokit-rails/adapters/postgis.rb
@@ -0,0 +1,22 @@
+module Geokit
+  module Adapters
+    class PostGIS < Abstract
+
+      def sphere_distance_sql(lat, lng, multiplier)
+        %|
+          (ACOS(least(1,COS(#{lat})*COS(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*COS(RADIANS(#{qualified_lng_column_name}))+
+          COS(#{lat})*SIN(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*SIN(RADIANS(#{qualified_lng_column_name}))+
+          SIN(#{lat})*SIN(RADIANS(#{qualified_lat_column_name}))))*#{multiplier})
+         |
+      end
+
+      def flat_distance_sql(origin, lat_degree_units, lng_degree_units)
+        %|
+          SQRT(POW(#{lat_degree_units}*(#{origin.lat}-#{qualified_lat_column_name}),2)+
+          POW(#{lng_degree_units}*(#{origin.lng}-#{qualified_lng_column_name}),2))
+         |
+      end
+
+    end
+  end
+end