"It is one thing to draw a map at random, set a scale in one corner of it at a venture and write up a story to the measurements. It is quite another to have to examine a whole book, make an inventory of all the allusions contained in it and, with a pair of compasses, painfully design a map to suit the data."
My First Book (Juvenilia) Robert Louis Stevenson
[Stevenson drew the first detailed 'Treasure Island' map to please his stepson, Lloyd Osbourne. When he discovered that the map had never reached his publishers, Cassell, it had to be redrawn, but it was never the same as his original. ]