Another option is to fill each area with a unique color, paste the map on a drawing canvas, and then use expressions like DrawingCanvas.SnapshotRedAt(x,y) to detect the color of clicked pixel. The canvas object itself can be invisible.
Thank you for your suggestion! However, I am now facing another issue...
I am using the canvas, but I still don’t quite understand where and how to use DrawingCanvas.SnapshotRedAt(x, y). Could you please explain this part in more detail? Thank you so much!