Oregon state's Cartography Group had a nice map a few years ago that did exactly this. Optimizing for global viewing when the full world was actually visible an

Oregon state's Cartography Group had a nice map a few years ago that did exactly this. Optimizing for global viewing when the full world was actually visible and adapting as you zoomed in until you ended up with Mercator at the closest points: http://cartography.oregonstate.edu/demos/AdaptiveCompositeMapProjections/ http://cartography.oregonstate.edu/demos/AdaptiveCompositeMa... (click the Projection Diagram tab at the bottom to see how it adapts based on zoom and latitude)