Geographic clustering

[gwk]

Hi,

I'm working on a search-on-map interface for our website. I've created a 
little proof of concept which uses the MarkerClusterer 
(http://code.google.com/p/gmaps-utility-library-dev/) which clusters the 
markers nicely. But because sending tens of thousands of markers over 
Ajax is not quite as fast as I would like it to be, I'd prefer to do the 
clustering on the server side. I've considered a few options like 
storing the morton-order and throwing away precision to cluster, 
assigning all locations to a grid position. Or simply cluster based on 
country/region/city depending on zoom level by adding latitude on 
longitude fields for each zoom level (so that for smaller countries you 
have to be zoomed in further to get the next level of clustering).

I was wondering if anybody else has worked on something similar and if 
so what their solutions are.

Regards,

gwk