Today it's data mapped by LRO Lunar Orbiter Laser Altimeter (LOLA)!
(And yes, I have had Whatever Lola Wants stuck in my head throughout working on this.)
Topographical modeling was done using an open source MATLAB script. As is described on the LRO-LOLA site, topography values are assigned based on deviation from a "base" sphere using mean Moon radius (i.e., the 0 value on the color scale).
Color schemes were chosen similarly to those in my Lunar Albedo maps, and should also be colorblind-friendly. I'm only concerned with nearside topography, since that is all we will be measuring using ground-based radars.