I'm trying to get the full rect of the used part of a tilemap and store the four sides in an array:
edgetiles = [
map_to_world(get_used_rect().size).y, \
map_to_world(get_used_rect().position).x, \
map_to_world(get_used_rect().position).y, \
map_to_world(get_used_rect().size).x
]
The problem is this gives me some strange values that don't correspond to the world coordinates of the isometric tilemap rect at all. My tilemap settings are:

Does this require some special setting to grab the edges in world space?