ElevationSampler

A cache of elevation values created from an elevation service or the GroundView used for synchronously querying elevation information for geometries. This class does not have a constructor. You can create an instance of this class by using ElevationLayer.createElevationSampler() or Ground.createElevationSampler() methods. The elevation sampler created from the Ground will sample data from the first elevation layer that has data available. To control the layer used for elevation sampling and the sampling resolution, use ElevationLayer.createElevationSampler().

map.ground.load()
  .then(function() {
    // create an elevation sampler from a given extent
    return view.map.ground.createElevationSampler(extent);
  })
  .then(function(elevationSampler) {
    // use the elevation sampler to get z-values for a point, multipoint or polyline geometry
    let zEnrichedGeometry = elevationSampler.queryElevation(geometry);
  });

An instance of this class is also available in GroundView.elevationSampler. This can be used when the elevation values need to reflect the elevation currently displayed in the view.

let elevationSampler = view.groundView.elevationSampler;
// listen for elevation changes in the view
elevationSampler.on('changed', function() {
  // enrich geometry with z-values from the elevation displayed in the view
  let zEnrichedGeometry = elevationSampler.queryElevation(point);
});