Impliment cluster arrangement for labels

[johnkellas]

Labels not overlapping

[christopherreay]

yes. Umm. this is to do with eumm... cluster analysis. christopher will do further analysis to the clustering sutff in cesium to determine how to take thedata and ceat a "datasource". etc

[TapdancingRodent]

How badly are the labels overlapping? Detecting colliding labels and adjusting them in code will be non-trivial so I'd advocate moving the cities a little bit or giving each city a manual label offset as part of the data input which we can definitely pull off in the short term.

[TapdancingRodent]

Given the varying scale I guess the quick fixes I suggested wouldn't work after all. Would it be enough to make sure that the labels are properly transparent so they aren't occluding each other? Looking at the source I can't work out why this isn't already the case.

[TapdancingRodent]

I've assigned this to myself - I'm going to try to work out if I can get the labels displaying through each other which is (as far as I can see) the best we can get in the timescale

[christopherreay]

Daniel, its already implemented, with pixelk offset collision https://cesiumjs.org/Cesium/Apps/Sandcastle/index.html?src=Clustering.html&label=Showcases

the issue is how to create a "data source", which is likely a behaviour of an "entitycollectiion"

[TapdancingRodent]

Nifty, OK, I'll leave it for now then and check if anything else is more urgent

[christopherreay]

are you going to study that>

e.g what we could do is set up an ftp server, where the node server reads the file system and implements whatever content is there.... KML loading is a thing.

what is the time frame you are working on>

[TapdancingRodent]

If you want me to look into it I can do that. I think I'll make a separate issue to look at how data is loaded, though, if we're going to make such large changes.

I have to clock off some time between 5 and 7pm tonight and I should have a couple of hours tomorrow morning, too.

[christopherreay]

aha: https://cesiumjs.org/Cesium/Build/Documentation/CustomDataSource.html

[christopherreay]

So hooray. Clustering turns on Boohoo, only the "point" part of the Entity shows after "un"clustering

[christopherreay]

Im going to try adding the point and label entities to different dataSource objects

[christopherreay]

I tried manually setting the "show" property of the text label, and it crashed Cesium :)

[johnkellas]

Currently running for me and seems to display a number for the amount of labels that are not shown. Interesting.

[christopherreay]

OK. so created two datasources, and turned on clustering Only for the Label dataSource

[christopherreay]

Ok, so change clustering behaviour to:

1. show the list of cities as the label for the cluster billboard
2. make a click on the cluster billboard zoom in

[TapdancingRodent]

Oh nuts, sorry I didn't see this earlier, you can turn on clustering separately for points and labels, let me find the docs

[TapdancingRodent]

According to the docs below it should be something along the lines of dataSource.clustering.clusterPoints = false;

https://cesiumjs.org/Cesium/Build/Documentation/DataSource.html#clustering https://cesiumjs.org/Cesium/Build/Documentation/EntityCluster.html#clusterPoints

[christopherreay]

yueah. I literally just read that same thing and came here to document it. Thanks

[christopherreay]

also its a bug in the unclustering code upstream. The clustering stuff is pretty edge case for them. They have been building it since 2013, and they have a roadmap to create generic force based and other strategies for "de-cluttering"

https://github.com/AnalyticalGraphicsInc/cesium/issues/1097

[christopherreay]

yes, that solves our use case

[christopherreay]

• [ ] make the cluster billboard selectable