I mapped out the whole fretboard on my computer one time on a long flight back from London. It was a pretty good challenge because all I really knew at the time was the tuning process and that the string order was maybe EADGBE or something like that. I eventually managed to get it all right despite a few false steps along the way. Picturing the piano keyboard helped a lot. Unfortunately I really don't spend much time on it now and need to be a little more disciplined to grind it into the old brain.