CesiumJs server-side clustering via Elasticsearch

The goal of this project was to make a server-side clustering view in CesiumJs. We use Elasticsearch for the backend (specifically GeoTileGridAggregation).

Flow

When a user moves his map the webapp calculates the top-left and bottom-right coordinates of his screen, which are then sent to the server that queries them in Elasticsearch and receives WMTS tiles as a response.

We take the tiles received from Elasticsearch and translates it to GeoJSON then we send it to the webapp which loads it as a GeoJsonDataSource in Cesium.

End Result

Why not use GeoHash aggregation

Rationale

We used WMTS based map server and thought we might be able to add the clustering via a new layer in the map server, the idea fell through, but we ended using the WMTS based GeoTile aggregation.

GeoHash

This demo could have been made using GeoHash, the only difference would have been the translation 'layer'. Instead of translation from WMTS, we would need to translate a GeoHash.

Both methods achieve the same result, only via a different "translation" medium.

Setup

• Load the geojson.json file into Elasticsearch (I did this via the Kibana UI).
• Change the Elasticsearch index in application.properties to your desired index.
• Run the application via gradle run - this will also build the webapp (make sure you have npm installed)
• Go to http:/localhost:8080/ (by defualt)