Question

Are there any examples of a google map that has one big canvas as an overlayview. I’m having a hard time positioning the canvas whenever the map zoom or pans.

Answer 1

Try the map bounds method, get the northeast and southwest view of current viewable map and use a js function to modify the overlay on each zoom to change the position dynamically.

mapBound = map.getBounds();
northEndOfMap =mapBound.getNorthEast(); 

and to get map zoom
map.getZoom();
Refer: http://code.google.com/apis/maps/documentation/javascript/reference.html#Map