private void MoveTree(PointerPoint imagePoint, PointerPoint canvasPoint)
        {
            if (BaumCollection != null)
            {
                Baum selectedTree = (Baum)BaumCollection.Where(x => x.IsMarked == true).FirstOrDefault();

                if (selectedTree != null)
                {
                    selectedTree.CanvasPosition = canvasPoint.Position;
                    selectedTree.ImagePosition  = imagePoint.Position;

                    BaumCollection.Remove(selectedTree);
                    BaumCollection.Add(selectedTree);
                }
            }
        }
        private void SetTree(PointerPoint imagePoint, PointerPoint canvasPoint)
        {
            Baum neuerBaum = new Baum();

            neuerBaum.CanvasPosition = canvasPoint.Position;
            neuerBaum.ImagePosition  = imagePoint.Position;

            neuerBaum.BaumNr = CurrentBaum.BaumNr;
            BaumCollection.Add(neuerBaum);
            SelectTree(neuerBaum);

            double i = mapImage.DesiredSize.Height;


            Messenger.Default.Send <SetBaumMessage>(new SetBaumMessage());
        }