diff --git a/src/BasicPathFinding.cs b/src/BasicPathFinding.cs
index 5d1e5e8..46cf205 100644
--- a/src/BasicPathFinding.cs
+++ b/src/BasicPathFinding.cs
@@ -143,8 +143,8 @@ namespace OpenSim.Modules.PathFinding
             {
                 for (int Y = 0; Y < m_scene.RegionInfo.RegionSizeY; Y++)
                 {
-                    int _imageX = (int)m_scene.RegionInfo.RegionSizeX - X;
-                    int _imageY = (int)m_scene.RegionInfo.RegionSizeY - Y;
+                    int _imageX = ((int)m_scene.RegionInfo.RegionSizeX - 1) - X;
+                    int _imageY = ((int)m_scene.RegionInfo.RegionSizeY - 1) - Y;
 
                     float baseheight = (float)m_scene.Heightmap[X, Y];