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SAS/STAT Software

SPP Procedure


The SPP procedure analyzes spatial point patterns. The broad goal of spatial point pattern analysis is to describe the occurrence of events (observations) that compose the pattern. The event locations are a discrete realization of a random spatial process. Therefore, the analysis goal is to investigate and characterize the original spatial process that generated the events in the spatial point pattern. The procedure's capabilities include the following:

  • fits an inhomogeneous Poisson process model and produce a variety of residual diagnostics
  • performs a simulation based goodness-of-fit test for the fitted intensity model
  • produces a nonparametric estimate of the first-order intensity
  • computes the F, G, J, K, L, and pair correlation functions and performs a test for complete spatial randomness based on these functions
  • performs a quadrat based test for complete spatial randomness
  • performs marked point pattern analysis by using character mark variables
  • automatically computes the study area bounds for the spatial point pattern by using the Ripley-Rasson estimator
  • performs covariate dependency tests that are based on an empirical distribution function
  • manages duplicate records
  • performs BY group processing, which enables you to obtain separate analyses on grouped observations
  • creates a SAS data set that corresponds to any output table
  • automatically creates graphs by using ODS Graphics

For further details see the SAS/STAT User's Guide: The SPP Procedure
( PDF | HTML )

Examples