X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/701325e9ef6720a16646c7218010e33b5c58d544..2c397321c9309eb9cd4dfed21375fc821a8d2d37:/app/helpers/application_helper.rb

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index ce0c5d67b..4aec9f5c1 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -125,6 +125,10 @@ module ApplicationHelper
     end
   end
 
+  def scale_to_zoom(scale)
+    Math.log(360.0 / (scale.to_f * 512.0)) / Math.log(2.0)
+  end
+
 private
 
   def javascript_strings_for_key(key)