Google Geo Developers Blog: MarkerClusterer: A Solution to the Too Many Markers Problem
http://googlegeodevelopers.blogspot.com/2009/04/markerclusterer-solution-to-t...
Perfect solution for displaying many markers at the same time in Google Maps.
http://googlegeodevelopers.blogspot.com/2009/04/markerclusterer-solution-to-t...
Perfect solution for displaying many markers at the same time in Google Maps.