[perilunar]

I think the ordering of coordinates for map regions makes more sense than the css margin/padding order:

rect: left, top, right, bottom

circle: cx,cy,r

poly: x1,y1,x2,y2,...

[danellis]

They both make sense for their respective use cases. An image has a fixed size. An HTML element does not necessarily. You can't measure the the right border from the left of an element if you don't know how big it is.