Identify clusters in SOM (Self Organizing Map)

cluster-analysis som
Wallter picture Wallter · Oct 25, 2012 · Viewed 12.9k times · Source

Once I have collected and organized data in a SOM how do I identify clusters?

(Items are aggregated and clustered using many traits - upwards of 10)

Specifically I want to find the 'center' of the cluster - therefor giving me the 'center' node(s).

Answer

pater picture pater · Oct 26, 2012

You could use a relative small map and consider each node a cluster, but this is far from optimal. If you want to apply an automated cluster detection method you should definitely read

Clustering of the Self−Organizing Map

and search similar bibliography.

You could also use more sophisticated versions of SOM algorithm (multi leveled, self growing, etc).

In any case, keep in mind that the problem of finding the "correct" number of clusters doesn't have a finite solution.

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