I'm trying to create a scalable metric grid where the 0,0 coordinates is in he middle of the plane. I must be able to import a image like a floorplan of a house and position and scale it on the ground plane to the correspond to the metric size of the grid. (10m wall on the floorplan must 10m in scale of the grid. If I click on any part of the grid it must give me the coordinates relative to the centered 0,0 coordinates, eg -7.32, 3.34 (in meters).

What must I use to accomplish this? I'm not use to WPF and program mostly in Windows Apps c#, but I will learn.