function GpxDataSource() {
  this._changed = new Event();
  this._error = new Event();
  this._loading = new Event();
  this._clock = undefined;
  this._entityCollection = new EntityCollection(this);
  this._entityCluster = new EntityCluster();
  this._name = undefined;
  this._version = undefined;
  this._creator = undefined;
  this._metadata = undefined;
  this._isLoading = false;
  this._pinBuilder = new PinBuilder();
}
A {@link DataSource} which processes the GPS Exchange Format (GPX).

@alias GpxDataSource
@constructor

@see {@link http://www.topografix.com/gpx.asp|Topografix GPX Standard}
@see {@link http://www.topografix.com/gpx/1/1/|Topografix GPX Documentation}

@demo {@link http://sandcastle.cesium.com/index.html?src=GPX.html}

@example
const viewer = new Cesium.Viewer('cesiumContainer');
viewer.dataSources.add(Cesium.GpxDataSource.load('../../SampleData/track.gpx'));