MAP - More and more ships are sweeping across the Northwest Passage as a heating planet clears a path for boat traffic through the Arctic corridor, raising hopes for commercial viability as well as concerns about the environmental and social impact. The Northwest Passage runs 1,450 kilometres from east to west, threading an archipelago of islands between Baffin Bay and the Beaufort Sea via a half-dozen routes under a single name. Effectively off-limit to transcontinental shipping for centuries, the seaway hosted a bulk freighter from end to end for the first time in 2013. The Canadian Press has prepared a map looking at the routes. This accompanies Northwest-Passage; THE CANADIAN PRESS/Sean Vokey