This has led to a dramatic increase in the number of visual clues presented to the system user, facilitating the interpretation of the pattern and location of burglaries (Hirshfield, Brown and Todd, 1995). .
1.3 Meeting Police Needs .
However, standard GIS packages may be of little use to the Crime Analyst, who may not have strongly focused queries but may instead be searching for meaningful patterns without knowing exactly where, when or what to look for (Openshaw, Cross and Waugh, 1993). As well as regular' GIS functions, there are two levels of crime analysis possible using most police GIS packages. The first is a synoptic overview of criminal activity for a given area of interest. The GIS can search for patterns in the crime data in time and space using graphic and database tools, within user-specified criteria, and can be used for testing hypotheses (though they are unable to generate such hypotheses themselves). The patterns searched for commonly include: .
(1) Hot Spot Mapping: By locating clusters of pins' on the computerised map it can be instantly seen where there are areas with a high risk of encountering criminal activity (see Figure 1). Identification of hotspots helps public safety institutions allocate .
Figure 1: Hot Spot Analysis using ArcView. .
(Source: Nulph, Burka and Mudd, 1997) .
resources for crime prevention activities. The GIS should be capable of detecting crime hotspots regardless of the locations of boundaries (such as police beats). Criminals do not limit their activities to such demarcation areas, and there have even been reported occasions where criminals have made deliberate use of county boundaries by crossing from one side to another to commit their crimes, in an attempt to confuse police detection techniques (Mitchell, 1993). The difficulty with generating hotspots is that it is largely an intuitive process and different methods are used by different pieces of software each producing different results (Agung, 1997).