markerclustererplus

The library creates and manages per-zoom-level clusters for large amounts of markers.

https://cdnjs.webstatic.cn/ajax/libs/markerclustererplus/2.1.4/markerclusterer.js
https://cdnjs.webstatic.cn/ajax/libs/markerclustererplus/2.1.4/markerclusterer.min.js