SpPack: spatial point pattern analysis in Excel using Visual Basic for Applications (VBA)

Many different sciences have developed many different tests to describe and characterise spatial point data. For example, all the trees in a given area may be mapped such that their x, y co-ordinates and other variables, or ‘marks’, (e.g. species, size) might be recorded. Statistical techniques can be used to explore interactions between events at different length scales and interactions between different types of events in the same area. SpPack is a menu-driven add-in for Excel written in Visual Basic for Applications (VBA) that provides a range of statistical analyses for spatial point data. These include simple nearest-neighbour-derived tests and more sophisticated second-order statistics such as Ripley’s K-function and the neighbourhood density function (NDF). Some simple grid or quadrat-based statistics are also calculated. The application of the SpPack add-in is demonstrated for artificially generated event sets with known properties and for a multi-type ecological event set.