Can I tell Cesium to use a zoom level with higher detail than needed, call it 'prefetch' behavior?

CesiumJS
1

Hi all, I'm relatively new to Cesium but really like a lot what I'm seeing. Best thing is to see the active developers and community!

However right now I miss the experience on how to achieve the following with the best detail/quality.

Let's say I've got a limited set of zoom levels available from an offline repository holding satellite imagery (next to OSM data). This repository is very well accessible to the Cesium application (ie local network):
Z=0
Z=5
Z=10
Z=15
Z=20

Right now when you set the zoom/camera to 4 for example it'll try to load zoom level 4, obviously this is not available in my example, so you'll be getting the very coarse grained picture from zoom level 0.

What I like to achieve is that the intermediate (missing) zoom levels will try to load and scale the tiles from the next best zoom level. See it as some sort of prefetching. Basically opposite to how it's working at this moment when you zoom in.

I Had a go at playing with the camera but couldn't manage to get an improvement. Missing tiles work relatively well when zooming out in case these are in cache, however zooming in beyond an available zoom level will always give me an ugly picture until reaching the next available zoom level...

Is it possible to tell Cesium to prefetch the tiles in such a way that for example when you look at the US you're actually looking at a zoomed out map that has detail corresponding more to a level you would see viewing states instead? Zooming in until reaching the 'state' zoomlevel should then not fetch new tiles, but just move the camera closer.

2

That would be of interest for me as well. In my case I would simply like to increase all zoom levels by one, to achieve a higher texture quality.

Is that possible over the API?

3

What you actually want to do is set the globe’s maximumScreenSpaceError property to 1, it defaults to 2. This trades off performance for improved visual quality. Here’s a snippet for enabling this with the Viewer.

var viewer = new Cesium.Viewer(‘cesiumContainer’);

viewer.scene.globe.maximumScreenSpaceError = 1;

4

Great, that’s what I needed!
Thank you.