I have in front of me a 'custom' map of an area I like to visit. It's just a representation of the area, so there's no real connection between the points on the 'custom' map (a) and how they would relate on a 'real', geographically correct map. As an example, think of how a ski resort map represents a ski area whilst looking nothing like a real map.
I'd like to take this custom map and, given some relationships between notable points on it and their actual lat/long co-ordinates, create a [x/y --> lat/long] co-ordinates map. Ideally, the more points I can relate to real lat/long co-ordinates, the more accurate this map should be.
The end result would allow me to take a lat/long co-ordinate (e.g. from GPS) and pin-point that location to a point on my custom map.