Have there been any studies around the usability of map clusters? I am talking about the practice of grouping together map markers into one object on a map when there is a high density of individual points.
Google Maps example: https://developers.google.com/maps/documentation/android/utility/marker-clustering
I am unable to find any research on whether this is better or worse than only showing individual points instead. I get the sense that it used to be a more common practice, but I'm not sure.
I can see some benefits to the practice, but have also noticed some problems when using maps that have this approach, so it would be nice to see if there is any data to support one or the other.