Which Clustering algorithm is used in grouping analysis?

Discussion created by johanness on Jan 28, 2013

I'd like to know which clustering algorithm is used in Grouping Analysis (Arc GIS 10.1). The tools information states that "The K-Means algorithm used to partition features into groups when NO_SPATIAL_CONSTRAINT is selected". So what about Clustering with spatial constraint? i guess it should be some hierarchical algorithm since my test result dind't show any variations at all (what is the case if no partitioning/k-means algorithm is applied --> Partitioning algorithms should show variations in their outputs)

So can anyone tell which algorithms are used to produce the results for spatially constraint clustering or how it works generally? Is it some kind of SOM (Self organizing map)?

Thx in advance.