In this paper we present a method for clustering gee-referenced data suitab
le for applications in spatial data mining, based on the medoid method. The
medoid method is related to k-MEANS, With the restriction that cluster rep
resentatives be chosen from among the data elements. Although the medoid me
thod in general produces clusters of high quality, especially in the presen
ce of noise, it is often criticized for the Omega (n(2)) time that it requi
res.
Our method incorporates both proximity and density information to achieve h
igh-quality clusters in sub-quadratic time; it does not require that the us
er specify the number of clusters in advance. The time bound is achieved by
means of a fast approximation to the medoid objective function, using Dela
unay triangulations to store proximity information.