Decide on region/projection/basemap mapping schema

[MattF-NSIDC]

Each "super" region (US West, Alaska, HMA, ...) has a projection. We need a way to represent this!

This file should also include basemaps for each projection.

First stab:

{ 
  "USWest": {"projection": "EPSG:3857", "basemaps": [...]},
  "Alaska": {"projection": "EPSG:9802", "basemaps": [...]},
}

[mfisher87]

Currently we are only using web mercator, and will come back to this question later.