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cluster-analysissom

Identify clusters in SOM (Self Organizing Map)

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).

Solution

  • 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.