nearest neighbour analysis

A technique for examining the spatial distribution of two-dimensionally recorded points, for example settlement sites within a river catchment. Assuming that all the points to be examined are contemporary and that all relevant examples are known, a series of statistics can be calculated by measuring the linear distance between sites. This can very easily be done using a GIS system. A nearest-neighbour index (usually denoted by the symbol R), is calculated from the ratio of the average observed distance from each point in the pattern to its nearest neighbour, to the average distance expected if the pattern were randomly distributed, which depends solely on the density of the pattern being studied. The index R varies from 0.00 for a totally clustered pattern through 1.00 for a random distribution to a maximum of 2.15 for a completely regularly spaced pattern.