Hah, that's possible too - but let me give you a quick pictoral example: http://i.imgur.com/m2WgE.png http://i.imgur.com/m2WgE.png The yellow line in that pic

Hah, that's possible too - but let me give you a quick pictoral example: http://i.imgur.com/m2WgE.png http://i.imgur.com/m2WgE.png The yellow line in that picture is 56 pixels long. Clearly, the size of the Australia overlay isn't perfectly accurate. But that's only a minor nitpick ;-)