Tile resolution

CesiumJS
1

Hi all!

I’ve checked that the quality of the map generated using the tile servers is worse compared to the original sources. If checked the resolution of the maps from OSM and they are more clear.

It seems that Cesium is not able to download the correct level of tiles depending on the camera height. Is there something that I could made with this?

Regards,

Jorge

2

I’ve found where Cesium select the correct tile level depending on the camera height (Scene/QuadTreePrimitive -> screenSpaceError). Increasing the returned value (e.g: multiplying the return value per 2) we are forcing to download tiles from other level with more resolution and the quality of the final map seems equals to the map from OSM.

Obviously, we are increasing the number of tiles and we are losing performance on it. I think that the screenSpaceError function has to be updated in order to return a most accurate error.

Regards,

Jorge

3

See Globe.maximumScreenSpaceError:
https://cesiumjs.org/Cesium/Build/Documentation/Globe.html#maximumScreenSpaceError

A good value to try is 4/3 (about 1.33) instead of the default of 2.

Kevin

4

Hi Kevin,

Can you explain why 4/3 is a good value?

At the moment we use a value of 1 for our application, to get the best visual quality.

Thanks, Willem

5

Hi Willem,

As the name implies, maximumScreenSpaceError is the maximum value. The way the LOD algorithm works, the minimum value ends up being half whatever the maximum value is. So with the default maximum of 2, the range is 1-2 pixels. If you change it to 1, the range is 0.5-1. I suggest 4/3 because that makes the range 0.66-1.33, which is centered on the “ideal” value of 1.

Kevin

6

Hi Kevin,

Thank you for the clarification !