[GIS] Dynamic GeoJSON on Cesium

cesiumczmlgeojsongeoserverreal time

I am trying to visualize live data that is updated every 5 seconds coming from a GeoJSON layer served by GeoServer.

What is the best way to do this on Cesium?

I saw that the GeoJsonDatasources in Cesium is intended only for static data, does this mean I have to convert my GeoJSON to CZML to be able to use the CzmlDataSource or it's a better choice to build a custom datasource and update the entities using the GeoJSON layer that is being served by GeoServer?

Best Answer

CZML works best when you know multiple points in time all at once, for example if you have received telemetry for a flight path, or have a mission plan set in the future, and you have a set of time-tagged geo locations that can be combined into a single CZML stream.

But, if you're stuck just polling for live data every so often, then you really just have a set of "static" points (frequently updated ones, perhaps, but not ones that have a time-ordered list of locations). In that case, CZML can't buy you much, and you're probably just as well polling for GeoJSON.

Related Solutions

Leaflet/GeoJSON – Custom Marker/Icon Based on Attribute Data

Ref: http://leafletjs.com/reference.html#icon

pointToLayer: function(feature, latlng) {
   var smallIcon = L.icon({
                      iconSize: [27, 27],
                      iconAnchor: [13, 27],
                      popupAnchor:  [1, -24],
                      iconUrl: 'leaflet/icons/' + feature.properties.pcp + '.png'
   });

   return L.marker(latlng, {icon: smallIcon});
}

If some markers share the same icon, you may want to create your icon objects before L.geoJson call

[GIS] Cesium.js time series data visualization

You are correct that ImageryProvider is currently designed only for static image data. Its implementation leverages the idea that the image tiles don't change once loaded. For example, it shows lower-resolution tiles for several animation frames while waiting for higher-resolution tiles to come down from the server. If all those tiles are changing every animation frame, the network won't be able to keep up at all. It would be megabytes of altered images every 1/30th second.
CZML simply feeds into Cesium's "Entity" API, which can also be driven by client-side JavaScript from any sort of time-dynamic data source. Cesium can display a lot of points simultaneously (see the Hurricane Demo) and with some JS code the styling could be user-selectable without even a round-trip back to the server. I don't know if this fits your particular case. You may need to edit your question to include more of the nature of the data you're trying to visualize.

Best Answer

Related Solutions

Leaflet/GeoJSON – Custom Marker/Icon Based on Attribute Data

[GIS] Cesium.js time series data visualization

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