Fill in the tile ID before saving a trace point. Also add appropriate

validation to the tracepoint model.

app/models/tracepoint.rb

@@ -1,24 +1,32 @@
 class Tracepoint < ActiveRecord::Base
   set_table_name 'gps_points'
 
-#  validates_numericality_of :latitude
+  validates_numericality_of :trackid, :only_integer => true
-#  validates_numericality_of :longitude
+  validates_numericality_of :latitude, :only_integer => true
+  validates_numericality_of :longitude, :only_integer => true
+  validates_associated :trace
+  validates_presence_of :timestamp
 
-  belongs_to :user
   belongs_to :trace, :foreign_key => 'gpx_id'
  
+  before_save :update_tile
+
   def self.find_by_area(minlat, minlon, maxlat, maxlon, options)
     self.with_scope(:find => {:conditions => OSM.sql_for_area(minlat, minlon, maxlat, maxlon)}) do
       return self.find(:all, options)
     end
   end
 
+  def update_tile
+    self.tile = QuadTile.tile_for_point(lat, lon)
+  end
+
   def lat=(l)
-    self.latitude = l * 1000000
+    self.latitude = (l * 1000000).round
   end
 
   def lng=(l)
-    self.longitude = l * 1000000
+    self.longitude = (l * 1000000).round
   end
 
   def lat