FlightPlanner :

When prefetching, do not download tile if file already exist
Add minZoom input in prefetch (like maxZoom)
Use Parallel.For instead of For to get tiles faster !

ExtLibs/GMap.NET.Core/GMap.NET/GMaps.cs

@@ -817,6 +817,31 @@ public PureImage GetImageFrom(GMapProvider provider, GPoint pos, int zoom, out E
 
       readonly Exception noDataException = new Exception("No data in local tile cache...");
 
+      public bool CheckImageExist(GMapProvider provider, GPoint pos, int zoom, out Exception result)
+      {
+         result = null;
+         try
+         {
+            if (Mode != AccessMode.ServerOnly && !provider.BypassCache)
+            {
+               if (PrimaryCache != null)
+               {
+                  return PrimaryCache.CheckImageFromCache(provider.DbId, pos, zoom);
+               }
+
+               if (SecondaryCache != null)
+               {
+                  return SecondaryCache.CheckImageFromCache(provider.DbId, pos, zoom);
+               }
+            }
+         }
+         catch (Exception ex)
+         {
+            Debug.WriteLine("CheckImageExist: " + ex.ToString());
+         }
+         return false;
+      }
+
 #if !PocketPC
       TileHttpHost host;
 

ExtLibs/GMap.NET.Core/GMap.NET/PureImageCache.cs

@@ -35,5 +35,14 @@ public interface PureImageCache
       /// <param name="type">provider dbid or null to use all providers</param>
       /// <returns>The number of deleted tiles.</returns>
       int DeleteOlderThan(DateTime date, int ? type);
+
+      /// <summary>
+      /// check if image exist on db
+      /// </summary>
+      /// <param name="type"></param>
+      /// <param name="pos"></param>
+      /// <param name="zoom"></param>
+      /// <returns>True if Image Exist, false otherwise</returns>
+      bool CheckImageFromCache(int type, GPoint pos, int zoom);
    }
 }