Geohash for fishnet locations

[KPGeo]

Need to select a geohash solution to apply to the fishnets to simplify and speed the mobility data processing and to enable a uniqueID for each cell in a common table.

[geohacker]

Per chat with @KPGeo, the use cases for geohash in this context are:

• unique ID for the fishnet cells
• aggregation and consolidation, and reduce the total volume used for analysis

I think it's better if use a quadkey approach. Each of the fishnet tile can get a unique quadkey that it falls in and this makes it easier to fetch within a bbox as well as aggregate higher levels. There also several client-side tools like tilebelt so we don't have to implement a custom geohash algorithm.

For implementation, we can either directly store the quadkey as a column in the table during import time or write a postgis function that fetches the quadkey id.

cc @guidorice @bitner @pieschker

[guidorice]

There also several client-side tools like tilebelt so we don't have to implement a custom geohash algorithm.

Also https://github.com/mapbox/tile-cover