A simple spatial classification of geo-data, by federated county; based on the regional planning infrastructure in California.
The hilited areas include:
Sacramento Area Council of Governments
AB32 Scoping Plan Update
Regional Profiles – All
San Diego Association of Governments
last but not least, at the State level
a simple numbering system via postgresql
region_id | region_name
-----------+---------------------
1 | northern_california
2 | sierra
3 | bay_area
4 | sacramento
5 | central_valley
6 | central_coast
7 | southern_california
8 | san_diego