Tiled imagery provider with irregular resolutions

CesiumJS
1

Hi,

In Ol3 a WMTS imagery provider may be configured with a pyramid with
non-linear resolutions. That is: when changing from one zoom level
to the next, the resolution is not divided by 2.

Cesium.WebMapTileServiceImageryProvider does not seem to support this.
Did I missed something? What would be needed to implement this?

Cheers,

Guillaume

Example defining a regular grid with Ol3:
http://openlayers.org/en/master/examples/wmts.html

2

Hi Guillaume,

Cesium doesn’t have any support for this in general. The assumption that the resolution is doubled at each level is baked into ImageryLayer (https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/ImageryLayer.js#L956) and possibly other places. It’s probably not terribly hard to fix, though, if there’s a reasonable motivation to do so. Do you have an example of a WMTS server that uses this feature?

Kevin

3

Hi Kevin,

Thank you for pointing the source.

Lots of high quality maps have been prepared (manually) for printing and
the resolutions of the set of them is irregular. It makes sense to be
able to use them.

Irregular resolution WMTS is used at http://map.geo.admin.ch : if you
zoom in and out you will notice that the scale is changing irregularily.

Guillaume