GIS

            
             Discuss the Range of Uses to Which Geographical Information Systems May be put in the Police Service.
            
             The geographical mapping of crimes is an important element of policing and even since the early 1900's paper maps have hung on the walls of police departments, covered in pins, used to represent crime events (Alexander, Groff and Hibdon, 1997). As pins are stuck into the map any existing spatial patterns begin to emerge, allowing the pattern of crime in a district to be analysed. The underlying assumption is that individual crimes are not unique random events, but rather share a number of common characteristics. .
             Although they have long been recognised as an aid to detection in policing circles, and indeed are regarded as the default first step' in a crime analysis operation (Nulph, Burka and Mudd, 1997), these pin maps have proved to be difficult to maintain, especially since the huge rise in reported crime during the 1980's and early 1990's (Openshaw, Cross and Waugh, 1993). The sheer volume of crime in many large urban areas has made interpreting these maps increasingly difficult, especially since there is no simple way of analysing crime patterns by factors such as the date of the crime, the time of day it took place, or the type of crime when using pin maps. .
             1.1 Introducing GIS into CPA .
             For these reasons the police have been quick to grasp the potential of geographic information systems (GIS) for Crime Pattern Analysis. GIS technologies appear to offer a simple way of automating, and indeed improving, the pin maps still used in many police stations today. As an example of this, Merseyside police have successfully used a system where 1:10000 Ordinance Surveys maps have been scanned into a computer to provide a raster backdrop over which a vector-based Arc/Info coverage have been plotted. To this map', the pins' - precisely spatially referenced property-based crime data - has been added.