dataSourceCollection order

[GE-KI62]

What happened?

Hi all,

I have a question about Cesium's DataSource rendering behavior that seems counterintuitive. I've noticed two specific behaviors that I'd like to understand better:

1. When adding multiple DataSources, newly added ones appear beneath older ones
2. The rendering order works from bottom to top, where entities at the bottom of the stack appear in front

Check the sandcastle link to see an example.

When running this example, you'll see that:

• the second DataSource is hidden by default since it's newer
• using lowerToBottom() actually makes it visible by putting it in front

Is this the expected behavior? It seems counterintuitive.

Thanks in advance!

Sandcastle example

https://sandcastle.cesium.com/#c=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

[ggetz]

Thanks for the report @GE-KI62!

Huh. This does seem to be unexpected, as least based on the behavior in the DataSource Order example. In that example, the second layer is shown above. And using "raise" and "lower" the first datasource does correspond to the order they imply.

I think it's something specific to GeoJSON datasource since CZML appears to be working as expected.