purplerabbits | (no subject)

I want a measuring wheel so I can measure how far I've walked (on the map, I don't want a big fuck off one I have to carry everywhere). The thing is that I can only find digital map wheels for over £20 which seems a bit excessive for the occasional egoboo, plus I can actually do the sums by myself, cos I am so clever. So where can I get a small wheel of known diameter, on a stick? Go on, you've a creative lot - think of something...

And yes, my first thought *was* a pin wheel or pastry cutter, but I don't want to make holes in my map...