Edited by David Weisburd and Tom McEwen
Crime maps have only recently begun to emerge as a significant tool in crime and justice. Until a decade ago, few criminal justice agencies had any capability for creating crime maps, and few investigators had the resources or patience to examine the spatial distribution of crime. Today, however, crime mapping is experiencing what might be termed an explosion of interest among both scholars and practitioners. This introduction begins by examining some early examples of mapping crime, focusing in particular on factors that inhibited the widespread integration of mapping into crime prevention research and practice in the past. It then turns to innovations in mapping technologies and crime prevention theory that have recently brought crime mapping to the center of trends in crime prevention. The final section introduces the contributions that follow and discusses how they illustrate the many uses of mapping in crime prevention. It examines the pitfalls and problems that researchers and practitioners are likely to encounter in developing and analyzing maps, and the potential advances in crime mapping we might expect in coming decades.
This chapter presents the main concepts of the GeoArchive as an "information foundation for community policing." Based on the Illinois Criminal Justice Information Authority's experience in developing this innovative idea, many agencies are using a GeoArchive to identify problems and develop strategies for crime prevention and intervention at the neighborhood level. The theory of the GeoArchive and practical suggestions and rules of thumb for developing a GeoArchive are illustrated with examples of how the GeoArchive is being used in current crime prevention strategies.
To address crime-related problems in their communities, police departments are increasingly involved in interagency work groups. As community policing and problem-oriented strategies are implemented, these groups are likely to include businesses, community organizations, and non-governmental agencies. Because these partnerships strive to reduce crime and disorder and to promote public safety, they often rely on police agencies for guidance. One of the tools that has promoted successful collaboration among the partners is geographical information, which focuses attention on the problems and needs of 7 particular neighborhood or community and uses the target area to garner community and government agency support for new initiatives.
Community policing is intended to change the way police officers at all levels work. In support of these changes, the police department's information system should also be modified, in ways that may not be immediately apparent; if it is not modified, the frill benefits of community policing may not be realized. This chapter describes the way the Chicago Police Department has reorganized its information system, and, more to the point, has changed its policies regarding the sharing of information, in support of a full implementation of community policing.
This paper identifies the challenges facing police departments that seek to implement computerized crime mapping systems. The first part of the paper highlights the importance of police departments identifying primary "end-users" and then designing systems that accomplish the tasks specific to the needs of their end-users. Data transfer, geocoding, data integration, system customization, and confidentiality issues are discussed. The second part of the paper illustrates the practicalities of implementing geographic mapping systems drawing from our experiences with the Drug Market Analysis Program. We profile the Jersey City, NJ crime mapping system to highlight some of the difficulties encountered in implementing a computerized crime mapping system for street-level use. The paper concludes that police departments planning to implement computer crime mapping capabilities need to think carefully about who, what, when, and how the system will be used and then design the system data sources and interfaces accordingly.
Analytic mapping and geographic databases are being increasingly recognized by police departments as an important tool in crime analysis, crime prevention and program evaluation. Improvements in technology, reasonably priced computer-based geographic information systems (GISs), and the availability of geographic data sources make it possible for law enforcement agencies to use analytic mapping. Police departments using automated mapping systems largely rely on attribute data associated with point locations to produce computer pin maps based on a variety or combination of crime event features. GISs can be used as a tool to identify factors contributing to crime, and thus allow police to proactively respond to the situations before they become problematic. This article will explore the use and possibilities of GIS by Baltimore County Police in describing and analyzing crime activity. Examples are included that demonstrate the potential of GIS in analyzing crime, developing interdiction strategies, and evaluating the effectiveness of prevention strategies. As this technology gains greater acceptance and use within police departments, it will become clear that the ability to produce automated pin maps is only one of many possible applications. Ultimately, GIS should be viewed as a tool for which police analysts could obtain a better understanding of criminal activity from a geographic perspective.
Preconceived notions can affect the job performance of community service recruits. In this investigation, the knowledge and perception of relative safety of recruits being trained to patrol central Philadelphia are compared with actual locations and safety levels of these neighborhoods to determine which communities were not perceived accurately. Results demonstrate that knowledge of the area did not translate into perceptions of safety. Rather, preconceived notions of the ethnic composition of the neighborhoods translated into notions of relative safety. These faulty impressions need to be corrected before recruits are assigned to serve this community.
The experience, observations, local knowledge, and historical perspective of working police officers and others with routine contact with offenders, communities, and criminal organizations may represent an important underutilized resource for describing, understanding, and crafting interventions aimed at crime problems. Mapping and other information collecting and -ordering techniques, usually aimed at formal police data, can also be used to good effect to capture and organize these experiential assets. This chapter describes one such exercise carried out as part of a project to apply problem-solving techniques to youth gun violence and gun markets in Boston. A working group comprised of Harvard University researchers, police officers from the Boston Police Department's Youth Violence Strike Force, probation officers cove-iing high-risk neighborhoods, and city-employed gang-mediation "street w0rkers": estimated the number and size of the city's gangs; mapped their turf, mapped their antagonisms and alliances; and classified five years of youth victimization events according to their connection (or lack thereof) to this gang geography. The products of these exercises provide: a "snapshot" of Boston's gang turf, an estimate of gang involvement in high-risk neighborhoods; a sociogram of gang relationships; and an estimate of Boston gangs' direct contribution to youth homicide victimization.
Crime can be analyzed and mapped in a number of different ways. This article compares maps of violent crime across the cities of British Columbia utilizing three crime measures: counts, rates and crime location quotients (LQCs). The LQC, adapted from regional planning, provides views of crime patterns not obtained with the two more traditional measures of crime. When used in conjunction with crime counts and rates, the LQC offers a way of understanding how one area is different from another for purposes of research and deployment of prevention and control resources.
While the police are trying to cone with large volumes of false alarm calls, a new direction in crime prevention asserts that preventing repeat victimization of people, property, places, and situations might be more efficient than other traditional crime prevention doctrines. Using graduated circle maps, this study compares the spatial distributions of alarm calls and burglary incidents across Charlotte, NC, during 1990. Specific comparisons are made regarding the spatial distributions and repeat-address natures of all burglar alarms, all burglaries, burglaries without alarms, and places producing both alarm calls and burglaries. Comparisons of tables indicate that burglaries are more of a single-address phenomenon than alarm calls. Map comparisons imply that the spatial distributions of alarms, and burglaries without alarms are different. Inferences are mode suggesting that premises with alarms might be responsible for displacing burglars to locations without alarms and that the sheer number of false alarms might subtract from any gains made by targeting places for repeat-burglary victimization.
The recent change in emphasis from reactive to proactive law enforcement, as evidenced by such concepts as community-oriented policing, has resulted in the need for tools to support these efforts. While geographic information systems (GISs) have been very successful at tracking criminal activity, proactive law enforcement requires systems that anticipate the emergence of criminal activity. One such system under development at Carnegie Mellon University and then Pittsburgh (PA) Bureau of Police is an early warning system that incorporates a GIS, previously developed to track criminal activity, and a relatively new technology - artificial neural networks - to predict the emergence or `flare ups" of drug hot-spot areas. The system obtains its input from cell-aggregated GIS-based data, processes the data with a previously trained artificial neural network and outputs the results to a choropleth map indicating those areas for which the network has predicted a relatively high number of 911 calls for service for drugs. The focus of this paper is to describe how the early warning system was developed, and to explain some of the underlying theory behind neural networks. In addition, the performance of the network is compared to some of the more traditional geographic forecasting methods.
Crime analysis has long relied on. maps for plotting crimes. Plotting crimes after they occur is a static process of historical data collection and reporting wherein data might not be plotted for many days, weeks, or months after the criminal event. SMART (Spatial Management, Analysis and Resource Tracking) mapping in law enforcement settings means integrating geographic information systems with dynamic location acquisition technology where near-real time data collection and analysis are possible. This article explores several possibilities for dynamic near-real time mapping applications for law enforcement. Examined are potential uses for small hand-held field equipment to plot "hot spots," boundaries, and other geographic characteristics, and for large automated vehicle location and artificial intelligence-guided emergency services dispatch.
Criminologists have expanded their use of maps as the costs of mapping have plummeted. Using two ruses of drug dealing, this paper examines the way in which theory influences how we interpret maps. The first study is a hypothetical case using fictitious data; the second, an actual case using real data. We show that when the explicit theoretical content of maps is low, it is difficult to interpret the data. As the theoretical content of maps increases, their utility increases. We show that theory also enhances the utility of computer algorithms designed to find point clusters on maps. The implications for crime contro! and prevention practitioners and researchers are discussed.