– print it on an A4 (8.5 x 11" for Yanks)
– hang it on the wall
– have a look standing at least 3 meters (yards) away
– flatten the whole thing in Photoshop
– blur it quite a lot, how much depends on size & resolution
– sit back and check it out
If you can still tell buildings from streets, it's cool. If not, maybe adjust it a bit.
Anyway, no question that it's a gorgeous map.