Ooh, I wouldn't know, sorry. I guess not though if you aren't finding it. I have an iphone.
The way I measure snakes is to get them to stretch out along a hallway wall. They usually straighten out and then I either use markers at the head and tail or use a tape measure. Another iPhone app I use CritterSize, where you take a picture of the snake with an object of a known length and trace the length of the snake and it calculates it for you. It's similar to that popular one people always link to on sites like this (but I'm forgetting what it is right now). It's always matched up with the measurement I got by hand, but I find it easier to measure in person. But I guess that can be difficult with some snakes.