Determine BoundingRectangle from an EntityCollection for use in Camera.flyTo

CesiumJS
1

Hello,

I'm looking for a way to determine the BoundingRectangle (or BoundingSphere) of an EntityCollection. When I was using straight Cesium, I could call Viewer.flyTo, but due to WebGL issues, I've moved to OL-Cesium (Openlayers for 2D, Cesium for 3D).

However, the OL-Cesium interface is lacking in some things, which requires me to access the Cesium 'innards' of OL-Cesium, and unfortunately, they do not use the Viewer class, but rather create a Scene, Camera, DataSourceDisplay, etc., separately.

So, I only have access to Camera.flyTo, which wants either a point or a BoundingRectangle.

My version of Cesium is 1.45.

Thanks.

2

Hi Dan,

I’m not sure what all you have access to in ol-cesium, but for reference, this is how we grab the bounding spheres in the Viewer class.

I think your best bet is to create a bounding sphere object for an individual entity from it’s vertices. You can create one bounding sphere from many with the BoundingSphere.fromBoundingSpheres function.

Thanks,

Gabby

3

Thanks Gabby! That worked perfectly...except for one minor detail:

I am performing this in the 'success' promise callback from the 'DataSourceCollection.add()' method of the DataSourceDisplay.dataSources property (e.g., dataSources.add(dataSource).then(function() { ...perform fly to...}); ). However, I have to throw in a few 'setTimeout()' calls, checking the DataSourceDisplay.ready property before performing the calculation. Otherwise, I get DeveloperErrors thrown (presumably because the dataSourceDisplay is not ready).

I looked for, but did not see, a callback on the DataSourceDisplay for 'ready' state. Is there a way for me to be notified of the 'ready' state?

Thanks,
Dan

4

Normally throughout the API, we have ready promises exposed. However in this case it doesn’t look there is one.

However, you can use when to wait on a ready property:

Cesium.when(dataSourceDisplay.ready, function () {

// callback code here

});

``