Understanding Crime Hotspots: GIS-Based Training

The course includes the following topics:

We'll define the term ‘hotspot’, explore the diagnostics of hotspots and discuss several key spatial theories that can be used to help explain why a hotspot may exist.

These statistics can provide a useful insight into the types of geographic patterns that exist in crime data before the data is displayed on a map. For example, these tests can be used to explore if evidence of spatial clustering exists and how dispersed the distribution is relative to other crime types or crime periods.

Point mapping is a common means of displaying crime events, but difficulties may arise in using this technique when handling large volumes of data or if locations of repeat events exist. We'll explore the practical uses of this technique.

Thematic mapping of crime data, aggregated to geographical administrative boundary areas such as census output areas, wards, or police beats, is a popular method for visually crime patterns.

However, problems exist with this technique that can cause misleading interpretations of where crime may be most prevalent. This can be due to freedom of choice in the different thematic range settings that are possible for displaying comparative levels of crime, and from the problems associated with a concept called the 'modifiable area unit problem'. We'll demonstrate how the technique can be used, and discuss its practical application.

Quadrat thematic mapping is a technique that uses uniform grid cells (quadrats) of a specified user width to thematically shade crime patterns. We'll explore the advantages and disadvantages of this technique for helping to determine and understand crime hotspots.

KDE is a method that aggregates points within a specified search radius, and creates a smooth continuous surface that represents the density of events distributed across the area. We'll go through tools that can be used to generate KDE hotspot maps and discusses the technique’s application. This includes discussion on the parameter settings that are required for KDE.