[GRASS-user] Re: algorithm used in i.cluster

Georg Kaspar georg at muenster.de
Thu Apr 22 11:35:21 EDT 2010


Sorry for flooding the list, but i found an interesting note in 
Schowengerdt (2007), p. 400:

"The ISODATA algorithm (Ball and Hall, 1967) is a common modification of 
the K-means algorithm and includes merging of clusters if their 
separation is below a threshold, and splitting of a single cluster into 
two clusters if it becomes too large"

The algorithm implemented in the i.cluster module involves merging of 
classes (I_cluster_merge) though no splitting function seems to be 
implemented.
Since Michael Shapiro stated that he might have used the K-means 
algorithm, I think we can be pretty shure that it is a modified version 
similar to the isodata algorithm, which is described as migrating means 
in Richards (2006).



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