Incorrect routes through the Northwest Pacific

[pjwilliams11]

This is an awesome and powerful package! One thing I've found: Routes through the Northwest Pacific are erroneous. It seems the base graph lacks sufficient points in the Northwest pacific to properly calculate a minimal distance route, leading to some weird routing. See the image below for a route between Shanghai and Vancouver - this should go north of Japan and generally follow a great circle route across the rest of the Pacific.