Override GetHashCode()

OSMDatastructure/Coordinates.cs

@@ -31,6 +31,11 @@ public class Coordinates
         return latHash * offset + lonHash;
     }
 
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(latitude, longitude);
+    }
+
     public ulong GetRegionHash()
     {
         float latRegion = this.latitude - this.latitude % Region.regionSize;