Some functions for analysing clusters and clustering of spatial point patterns.
See package spatstat for more details on point pattern analysis, especially Section II: Exploratory Data Analysis.
This package provides functional summaries for analysing stationary and isotropic point patterns in 2D and 3D.
Connectivity function, smoothed and cumulative
Clustering function, generalisation of clustering coefficient
Triangle/triplet intensity function
The Ripley's K-function is there as well as spatstat does not support 3D.
The main source for the definitions of connectivity and clustering functions is Rajala: Spatial clustering and graph based statistical features, JYU preprints, 2010