Marker clustering for internet map viewers.
Use the free service to group simple markers into cluster markers on a zoom level basis.
Check the appearance of sample clustered datasets, or upload your own data ...
A map viewer can be used to search through a geolocalized database with a map viewer.
It's not just about the appearance: use data summaries and lists of IDs assigned to clusters.
The desktop application allows you to process data faster, more safely, and provides additional clustering/generalization functionalities.
Read info and visit websites providing info about internet mapping, marker clustering, geometry generalization, and related topics.