X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/3d906fe8c6303c00e399ce2dfecc3471959fbe6e..0b6f0c1d34f636c0cdde234f3a62a6ead2b8655f:/lib/osm.rb

diff --git a/lib/osm.rb b/lib/osm.rb
index 5be2da56a..789a5f439 100644
--- a/lib/osm.rb
+++ b/lib/osm.rb
@@ -334,6 +334,11 @@ module OSM
       maxlon = (@lon + lonradius) * 180 / PI
       return { :minlat => minlat, :maxlat => maxlat, :minlon => minlon, :maxlon => maxlon }
     end
+
+    # get the SQL to use to calculate distance
+    def sql_for_distance(lat_field, lon_field)
+      "6372.795 * 2 * asin(sqrt(power(sin((radians(#{lat_field}) - #{@lat}) / 2), 2) + cos(#{@lat}) * cos(radians(#{lat_field})) * power(sin((radians(#{lon_field}) - #{@lon})/2), 2)))"
+    end
   end
 
   class GeoRSS