H3 layer for statistic summaries of geospatial data

[robyngit]

We have discussed the idea of rendering H3 grid cells in Cesium to display summaries of geo-spaital datasets. It would be possible to render these on the fly as "ground primitives" similar to what we do currently for geohashes. This way they could drape over terrain. We would just need a source from which to get values for each grid cell. Cesium could then map colours to each value dynamically (i.e. the colour palette could be changed in the UI).

@datadavev has come up with a nice proof of concept showing that it's pretty easy to generate: https://gist.github.com/datadavev/eb4f70bd8f98593b6b8aa42a366ffe46

This came up for the PDG data layers specifically, but could be applicable to many different groups and datasets