GeoSurveillance is software that combines spatial statistical routines with some basic Geographic Information Systems (GIS) functions to carry out retrospective and prospective statistical tests for the detection of geographic clustering. In this software, the focus is primarily on the spatial statistical analysis. Consequently, full GIS functionality is not provided. GIS functions are limited to map-display related operations, such as loading maps, coloring based on legend schemes predefined internally, zooming in, zooming out, panning, etc. If necessary, the analysis results can be saved so that they can be conveniently used in other commercial GIS if more sophisticated GIS operations are required.