See:
http://postgis.refractions.net/pipermail/postgis-users/2006-March/011324.html
Heinz-Josef Lücking wrote:
Is the code of Schuyler available online or do i have to buy that book?
We where thinking about use of K-means for clustering too. Could you
pleae tell me more about the K-means-PostGIS-PostGres thing?
Heinz-Josef Lücking
Fawcett, David schrieb:
You can see Schuyler's code working at:
http://mappinghacks.com/projects/gmaps/cluster.html
In the Google Maps Hacks book, Schuyler makes a pretty good case for
why the tiling approach over K-means for on-the-fly mapping.
That said, I know of one person doing K-means to cluster points. This
is implemented using PostGIS and Postgres-R. Anyone, Bitner?!
David.
-----Original Message-----
From: UMN MapServer Users List [mailto:[EMAIL PROTECTED]
On Behalf Of Schuyler Erle
Sent: Thursday, April 06, 2006 8:01 AM
To: [email protected]
Subject: Re: [UMN_MAPSERVER-USERS] clustering points
* On 6-Apr-2006 at 2:57AM PDT, Heinz-Josef Lücking said:
I?m looking for a solution or hints on clustering points depending on
distance. I would like to have just one symbol with diferent sizes
depending on how many points are "behind" that symbol.
I did some experiments with this for Google Maps Hacks, and I found
that the fastest way to do this for a map display is to imagine a grid
over your map view such that each cell would have the display size of
your marker icon. Assign each of your points to the grid cell that
contains it. Finally, for each grid cell that contains a point,
display a marker on the map for that cell. The marker can vary based
on the number of points the cell contains.
SDE
