[OpenLayers-Users] Cluster strategy but on the server side

Yves Moisan yves.moisan at boreal-is.com
Sat Apr 4 11:45:32 EDT 2009


> 
> I don't know if this is interesting for you but this postgis thread was
> related to the subject of your mail :
> 
> http://postgis.refractions.net/pipermail/postgis-users/2005-July/008642.html
> 
That series of posts is about statistical data clustering as in k-means
and the like.  Give a k-means like algorithm a number of seeds N, it
will minimize some sum of squares of distances between those seed points
and the data points and your N clusters will be produced.  

That's not how the clustering strategy in OL is implemented AFAIK.  Come
to think of it a pregenerated set of clusters could be done on distance
to seed points (e.g. know site locations ?), but that would need to be
done for every zoom level and even every "tile" in a given zoom level.  

The idea is to bring the number of features down to something manageable
by the browser, so maybe some server-side clustering could be used to
produce 100's of "compound features" that a server-side clustering
strategy could further refine ?

Come FF 3.5 with a faster JS engine ;-)

Cheers,

Yves

> --
> Didrik
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