if you have a digital camera, i don't see why that wouldn't work - it's not too different from scanning once you get it in there. I'd recommend fastening the paper to a wall, and having the camera sitting on a stable surface (tripod, or a table) so that you can get a perfectly straight-on shot. You could try getting the whole thing in one shot and see if that's workable, or if you need more detail, take a number of smaller detail pics - this is where the straight-on becomes important, when you try stitching the detail shots together afterwards.

I haven't taken photos of maps, per se, but there's a number of artwork pieces that I've digitized using this method. Either way it would be the same process.