Nearest Neighbor Methods

Nearest neighbor (NN) methods include at least six different groups of statistical methods. All have in common the idea that some aspect of the similarity between a point and its NN can be used to make useful inferences. In some cases, the similarity is the distance between the point and its NN; in others, the appropriate similarity is based on other identifying characteristics of the points. I will discuss in detail NN methods for studying spatial point processes and analyzing field experiments because both are commonly used in biology and environmetrics. I will very briefly discuss NN designs for field experiments. I will not discuss NN estimates of probability density functions (pdfs) [24], NN methods for discrimination or classification [61], or NN linkage (i.e. simple linkage) in hierarchical clustering [32], pp. 73–84. Although these last three methods have been applied to environmetric data, they are much more general.