CZML Exporter

[OmarShehata]

I was surprised to see there wasn't a way to export a CesiumJS scene using CZML! I think this would be pretty useful, in this particular case on the forum they're trying to save the entities they're drawing in their app. This could be something like how a JSON.stringify() will take an object and serialize it. We can have a viewer.entities.toCZML which will serialize an entity collection.

[OmarShehata]

After seeing the new KML export class here #7921, I think this could be a good first contribution (not trivial, but not too involved either), and I can imagine it being very useful for a variety of use cases. The linked PR could be a good reference.

[OmarShehata]

Here's a community Sandcastle to export a Cesium scene as GeoJSON! https://groups.google.com/d/msg/cesium-dev/KT2brToFGR8/sdUjxNfCEAAJ

[icemagno]

Hi all. The Sandcastle example pointed by Omar is not working anymore.

Uncaught TypeError: Cannot read properties of undefined (reading 'x') (on line 172)

Has something changed from Sep, 2019 to now ?

This feature is a very important missing feature. GeoJSON is a standard and I think Cesium could export its elements to it.
it's worth remembering Cesium can read GeoJSON directly so why it cannot write?

[icemagno]

About the error:

Use hierarchy._value.positions[0].x instead hierarchy._value[0].x