Etymology of 'map' as 'a person's face'

1899   A. H. Lewis Sandburrs 9,   I sees d' map of a skirt—a goil, I means, on a drop curtain at a swell t'eatre once. 

1902   G. V. Hobart It's up to You iv. 78   It was Benedict Murgatoyd—the lad with the map like a cow! 

1908   K. McGaffey Sorrows of Show Girl 200   Hauling off wifey hangs one on Alla's map. 

1922   P. G. Wodehouse Clicking of Cuthbert ix. 205   The portrait..was that of a man in the early thirties... ‘What a map!’ exclaimed the young man. 

1935   P. G. Wodehouse Luck of Bodkins xv. 178   It's mostly a case of having a map that photographs well. 

1936   ‘J. Curtis’ Gilt Kid xiv. 144   What d'you want to sit there staring at me for? I'm not a bloody oil-painting. You ought to know my map by now. 

1971   J. Curtis Banjo 255   No mistaking that map. 

1996   D. F. Wallace Infinite Jest 280   That look on your map there mean something there, Randy?