Visually connect features that are duplicates of each other

[lonvia]

Layers like 'place nodes close' always have groups of features that belong together. It would be nice to have a visual hint where the other feature is instead of the simple object ID.

[AntoJvlt]

To do that more easily and to not add to much overhead on the front side, we should add a generic pattern to add features in some groups on the server side, for example by adding a property feature-group: 1 to the feature. By doing that we could easily identify if two features are in the same group on the front end side.

For the visual effect, some tests should be done at it won't be that easy since we are manipulating vector tiles features. What do you think could be a nice visual effect to add? I was thinking of linking them with some connection strokes.

[lonvia]

Another option is to put the affected objects into one feature and add a MultiPoint geometry with all the center points.