Custom Maps lets you track your GPS position on paper maps

Custom Maps is one of those original ideas you never thought you'd need until it was presented to you. Basically, it's an app that lets you turn any map (or an image of one) which happens to line up with region available in Google Maps into a GPS map. What the map? Okay, say you have a photo of a paper map or brochure, like these you'd find at the entrances of parks and zoos. It can even be a screenshot of a .PDF map you have laying around. What you have to do after is line up at least two, or more points that match the map image with Google Maps. If the spell works as advertised, Custom Maps will ...