Being a bit of an out of the way place, It can be difficult to find good mapping for Greenland. Saga maps produce a couple of really nice maps of the Ammassalik area fortunately but there is nothing available from the major gps manufacturers.
I use a Garmin GPSMAP62s GPS, a robust and useful GPS but no decent maps of Greenland are available for it. Soooo, one of the really nifty features of some Garmin products is the ability to load georeferenced scanned paper maps in. The end result is an accurate, highly detailed map. Below are a couple of screenshots from the Custom maps I loaded into the GPS compared to the world base map that came with the GPS. Pretty cool huh?