Hints wanted re: Dealing with stacks of shapewise-identical polygons

CesiumJS
1

Hi Cesium community,

My Cesium app has to deal with some cases in which the polygons associated with distinct entities happen to be geometrically identical.

This creates an interesting problem where highlighting polygons by changing their edge color temporarily doesn’t work; polygons elsewhere in the stack seem to be hiding the changed edge color.

It would be good if my user could click in the area of the stack and get information about the properties of each polygon under the point that they clicked. Currently they only get the standard Cesium popup about the polygon at the top of the stack. Is there a nice way to make this happen?

Can anyone offer me some general wisdom about getting this sort of stack under control? Is there a way e.g. to ensure that a particular item shows up on the top of the stack, where the user can perceive changes to its material properties?

Thanks!

A

2

Cesium doesn’t have a way to order polygons on the ground yet, but it will in the near future. Work is being done as part of this pull request: https://github.com/AnalyticalGraphicsInc/cesium/pull/2865 Other than offsetting detecting identical geometry and offsetting the height, I’m not sure there are a lot of options for having one particular polygon stand out.

You can use scene.drillPick to select multiple items at once, but the InfoBox widget doesn’t have any kind of support for showing them so you would have to either provide your own InfoBox (or custom widget) and disable the built in one, or create a pseudo-entity from the multiple-picked items and generate a custom description that lists them all. (or a separate pop-up completely and lets a user choose which one to show in the InfoBox). There’s obviously a lot of options depending on exactly how you want it to work.