SPATCLUS: an R package for arbitrarily shaped multiple spatial cluster detection for case event data.

This paper describes an R package, named SPATCLUS that implements a method recently proposed for spatial cluster detection of case event data. This method is based on a data transformation. This transformation is achieved by the definition of a trajectory, which allows to attribute to each point a selection order and the distance to its nearest neighbour. The nearest point is searched among the points which have not yet been selected in the trajectory. Due to the trajectory effects, the distance is weighted by the expected distance under the uniform distribution hypothesis. Potential clusters are located by using multiple structural change models and a dynamic programming algorithm. The double maximum test allows to select the best model. The significativity of potential clusters is determined by Monte Carlo simulations. This method makes it possible the detection of multiple clusters of any shape.