We have both a road and a handheld GPS (loan) but are not highly techie and have been unable to find digital maps to use with them.
However, on Amazon, I found two paper charts which we both love:
Patagonian and Fuegian Channels;Chilean Fjords cruise chart
Ushuaia to Antarctica;Drake Passage;Polar Voyage Log Map
both pub by Zagier & Urraty. They are large, glossy paper, have lat and long along the margins, text is mixed Spanish/English, show water depth, ships names for explorers/shipwrecks/ etc., etc. My husband is a sailor and is very pleased with these. Not very expensive.
August 2013 HAL Zaandam, Seward to Vancouver
6 Jan 2011 - HAL Veendam SA & Antarctica
12 April 2008 - Cunard QE2 Transatlantic NYC to Southampton