A reference to the CesiumGeohash MapAsset model that is rendered in this view
Draws the geohash polygons on the Cesium map (via
CesiumGeohash) associated with this view. Draws a number representing the
count/density associated with that polygon (e.g. number of datasets in that area).
Listens to Cesium Camera movement so the geohash level can change when the camera zooms in