We are all accustom to yardage books when we play golf. Included in the yardage books is a layout of the green, which will have overall dimensions and respective topology. We really do not need the yardages for the fairways etc. But having a green map would be interesting.
You could sell each course separately, and allow the user to input pin placements within a grid on the map.
Might prove interesting, since all I use is the perspective of the green, on my approach shots.