My name is XIAO Juguang - just call me Juguang. I am a freelance software developer based in Beijing, China. Technically speaking, I'm double sided. On one side, I specialize in knowledge management and business modeling, traditionally using LAMP and now experimenting with offerings like Google App Engine. On the other side, I love visualization in time and space, with charts, trees, graphs, and maps, always using the power of ActionScript/Flex, with the help of open-source projects like Degrafa, Axiis, and Birdeye, and of course, APIs like the Google Maps API for Flash.
To see how the AS3 MarkerClusterer works, try out the demo (shown above). As you zoom and pan the map, you can witness how the markers are clustered and re-clustered. To learn how to use MarkerClusterer on your own map, view the source code of the demo. To use the library, check out the source code and import it into your project.
The current algorithm is quite simple, just clustering markers in a grid and using static images for the cluster markers. Future extensions could include support for regional clustering or using arbitrary DisplayObjects for the cluster markers. If you're interested in extending the library, join the project.