rendering KML "superoverlays"

CesiumJS
1

Dear Developers,

I ran into a problem while displaying KML files in Cesium. If the KML file contains "superoverlays" - a multi-resolution image pyramid of groundOverlays, produced e.g. with Global Mapper - rendering will be ugly as Regions and LODs assigned to GroundOverlay elements seem not to take effect.

such a KMZ file is here:
http://mercator.elte.hu/~saman/cesium/blaeu_eg.kmz

As a temporary solution, I can hide all those Rectangles from KmlDataSource entities, that have bounding boxes that entirely contain other Rectangles from the same source (meaning that they are lower-resolution images)

sample code is here:

http://mercator.elte.hu/~saman/cesium/groundoverlay.html

After loading, zoom in to see the rendering problem. Press the button in the top left corner to hide lower resolution images causing the problem.

If there is a better solution, please let me know.

Best,
Mátyás

2

Hi Mátyás,

That’s a really neat overlay!

Cesium doesn’t currently support superoverlays. It is something that’s on our longterm KML roadmap: https://github.com/AnalyticalGraphicsInc/cesium/issues/873

You might be able to load this using some kind of imagery provider. We have a UrlTemplateImageryProvider that you can use to specifiy your own URL template for fetching tiles.

Best,

Hannah

3

Dear Hannah,

Thanks for the quick answer. (By the way, the overlay is the digitised version of a 17th century celestial globe.)
The problem is that the overlays I'd like to display are provided as KMZ files on the web. So far this solution seems to work, but if I have some time, I'll try to figure out a more elegant way.

Best,
Mátyás

2016. április 4., hétfő 16:51:50 UTC+2 időpontban Hannah Pinkos a következőt írta: