Anton Balazh has an amazing relief map with the best ocean material I have ever seen. This link has several examples: http://unofficialnetworks.com/2014/06/detailed-relief-maps-show-worlds-mountain-ranges
I am close to recreating the land (although more than happy to accept recommendations on improving that as well!) but the ocean is well beyond my current capabilities.
I have found several tutorials on creating some good looking procedural ocean materials (some of my favorites include avoiding a tiled looking ocean simulation and Prevent ocean from behaving like a mirror) with one of the best being https://blenderartists.org/forum/showthread.php?320054-Test-Tutorial-Realistic-tropical-water-shader-in-Cycles
The challenge is I'm using images from NASA (http://visibleearth.nasa.gov/view_cat.php?categoryID=1484&p=1) to both texture the land and create the height field. NASA has posted a bathymetry map and a ocean mask, but I can't figure out how to combine all of these to get the subtle ocean bathymetry effect and depth coloring effect. To complicate matters even more, I prefer using the highly detailed images which don't have a premade ocean mask.
Any suggestions are greatly appreciated. Thanks!