X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/dd33fc633c1bcd2ab4ecfc412ffe5edf43491cec..da76d64e93fc2892ab567f4ca6dc9a6eac4385b6:/app/models/geo_record.rb

diff --git a/app/models/geo_record.rb b/app/models/geo_record.rb
index 12a2a643e..08808d352 100644
--- a/app/models/geo_record.rb
+++ b/app/models/geo_record.rb
@@ -19,11 +19,30 @@ class GeoRecord < ActiveRecord::Base
     self.longitude = (l * 10000000).round
   end
 
+  # Return WGS84 latitude
   def lat
     return self.latitude.to_f / 10000000
   end
 
+  # Return WGS84 longitude
   def lon
     return self.longitude.to_f / 10000000
   end
+
+  # Potlatch projections
+  def lon_potlatch(baselong,masterscale)
+    (self.lon-baselong)*masterscale
+  end
+
+  def lat_potlatch(basey,masterscale)
+    -(lat2y(self.lat)-basey)*masterscale
+  end
+  
+  private
+  
+  def lat2y(a)
+    180/Math::PI * Math.log(Math.tan(Math::PI/4+a*(Math::PI/180)/2))
+  end
+
 end
+