Friday, November 21, 2008

Crime Analysis And GIS


COMSTAT, and other GIS crime mapping applications have since become widespread and almost commonplace in law enforcement agencies nationwide as well as worldwide. Probably one of the most invaluable tools available for effective crime fighting is information. Using maps to display that information is an old tool. The advent of desktop computers has significantly increased the role of computer mapping. The availability of low-cost and user-friendly GIS applications has further served to increase the use of GIS in crime mapping. The 1994 Violent Crime Control and Law Enforcement Act provided a boost to the implementation of GIS by providing funding for crime prevention programs. The added functionality of a GIS over computer mapping has increased the capabilities of crime fighting. GIS’ replacement of paper-based or flat file searching increases the efficiency and speed of the analysis.
GIS helps crime analysis in many ways. The foremost use is to visualize crime occurrences. This allows law enforcement agencies to understand where crime is occurring as well as determine if there are any patterns. Areas of high crime density are known as hot spots. Hot spot analysis is a valuable tool as it allows police to not only identify areas of high crime but also explore variables that are affecting crime patterns. For example, mapping drug arrests may show an increased density around locations that have public telephones. With this information, law enforcement agencies can be more efficient in their crime fighting tactics from increasing patrols around such locations or by proactive measures by removing problematic public phones that persistently attract drug transactions.
As the use of GIS evolves in crime analysis, new and innovative applications are emerging. One of the latest examples of such creativeness is the use of GIS to triangulate gunfire. In conjunction with consultants, the Police Department in Redwood City, California implemented ShotSpotter. This application uses strategically placed microphones in conjunction with GIS to locate gunshots using triangulation. The application, created with ESRI’s MapObjects, can then search the property information to determine the address of the nearest residence or business to the gunfire. The inventiveness of this program earned it an induction by the Smithsonian Institute into its 2000 Information Technology Innovation Collection.
Crime Mapping on the Web
With the increase of GIS in crime mapping has come increased public access to crime data. The most accessible and popular method emerging is through Internet access. In 1995, the Police Department of Vacaville, California was one of the first law enforcement agencies to put crime maps on the web. Now, there are many agencies that publish their crime data via the Internet.
Not everyone is happy about the proliferation of crime data on the Internet. Real estate developers and agents feel that public crime data in high crime data will lower housing prices. As with most debates about web publishing of GIS data, right-to-privacy advocates worry about backlashes towards former felons especially convicted sex offenders and domestic violence criminals. The reality of the situation is that most of this information is public information (check the crime blotter section of your local newspaper) although the ease of crime mapping makes this information more readily available.

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