Pick/drillpick imagery layer

This was requested on the forum to be able to use something like scene.pick(mousePosition) and get which imagery layer(s) are at that location:

Most of our use cases are about picking local imagery and doing things with them. They often overlap, but can also stand on their own, and there’s functionality associated with each, even a multitude (like a spreadsheet associated with several orthos spread out across a local area).

I think this should be fairly straightforward to compute in your application, given that you know the extents of the imagery ahead of time, can convert the mouse position to a location on the globe, and see which rectangles have that position inside, but perhaps this is something that can be built-in if it’s a common use case?

[shelterit]

And just to add some additional .2$, as a developer I’d love to leave the Cesium map to Cesium, and so if I click on the map, Cesium should be able to tell me what I clicked on. That it only does this for some things on the map seems a bit odd since Cesium put those things there.

Yes, I can write all sorts of code to simulate a click handler, and we already have a layers stack so I can work it out from there. But it would be great if, say, the drillPick(…) can return entities, imageProviders, tileSets, etc. so that my interaction point with Cesium is limited and focused. Makes for better code. 😃

[lilleyse]

Opened a separate issue for pixel perfect picking: https://github.com/CesiumGS/cesium/issues/9695