Introduction - If you have any usage issues, please Google them yourself
Density Based Spatial Clustering of Applications of Noise
Uses a density-based notion of clusters to discover clusters of arbitrary shapes, in spatial databases
Key idea: for each object of a cluster, the neighborhood of a given radius contains at least a minimum number of data-objects. (i.e. the density of each cluster must exceed a threshold value)
Choosing the distance function is the critical parameter.
An object that appears to be part of Noise at present, might, at a later stage, be included into one of the clusters.