Bedmap2 was created by the British Antarctic Survey, and used decades of data to produce this detailed view of the frozen continent. NASA’s contribution to the dataset includes surface measurements from its now-retired orbiting Ice, Cloud, and Land Elevation Satellite (ICESat), and results from several years of flyovers by specialized aircraft that collected radar and other data measuring changes in the thickness of sea ice, glaciers, and ice sheets as part of Operation IceBridge.
The work improves on the decade-old Bedmap project, which virtually thawed the continent, but at lower resolution. Both maps combine information on ice thickness, bedrock topography, and surface elevation. Bedmap2 added millions of extra data points and also covers a wider swath of land than its predecessor. Over on NASA’s site, you can compare the two datasets by sliding between them.