Change the coordinate system of a Canvas in WPF

Question

I\'m writing a mapping app that uses a Canvas for positioning elements. For each element I have to programatically convert element\'s Lat/Long to the canvas\' coordinate, then

Answer 1

I was able to get it to by creating my own custom canvas and overriding the ArrangeOverride function like so:

    public class CustomCanvas : Canvas
    {
        protected override Size ArrangeOverride(Size arrangeSize)
        {
            foreach (UIElement child in InternalChildren)
            {
                double left = Canvas.GetLeft(child);
                double top = Canvas.GetTop(child);
                Point canvasPoint = ToCanvas(top, left);
                child.Arrange(new Rect(canvasPoint, child.DesiredSize));
            }
            return arrangeSize;
        }
        Point ToCanvas(double lat, double lon)
        {
            double x = this.Width / 360;
            x *= (lon - -180);
            double y = this.Height / 180;
            y *= -(lat + -90);
            return new Point(x, y);
        }
    }

Which works for my described problem, but it probably would not work for another need I have, which is a PathGeometry. It wouldn't work because the points are not defined as Top and Left, but as actual points.