I am currently clustering hundreds of markers on my google maps. Many of the markers are based on geo-coded addresses, which at times only resolve to the city level. Normally i will end up with lets say a few hundred addresses all with the same lat lon for example in the middle of New York City.
I know about the Marker Clustering in google maps, however when all the markers have the same lat long, you loose the ability to click on each marker, and bring up a popup.
How can I manage these markers in such a way when you zoom in you can still tell how many markers there are, and still click on them?
Look at the OverlappingMarkerSpiderfier
See this post on integrating it with MarkerClusterer
I had a similar (albeit not exactly the same) problem.
I needed to draw sample points in a plot chart. But I found collisions (exact overlap for some points coming from coarser lectures) and aliasing artifacts (partial overlaps with repeating some fixed amount of displacement due also to coarser lectures).
I decided to introduce some random displacements to all of the points. The "noise" had a normal distribution with a variance two times smaller than the variance of the measured error of the sample, so it did not change add significant variance to the perceived sample. The result was a much clearer chart, more informative, and nicer.
Applying this experience in your case, I would detect exact overlaps in Lat Long and for those I would add some random Lat and Long, effectively moving the point a bit away of its original position and thus avoiding the exact overlap.
来源：https://stackoverflow.com/questions/11781183/how-can-i-cluster-markers-without-overlap-with-google-maps