Crime Mapping and Analysis Program

Abstract: The new century brings with it growing interest in crime places. This interest spans theory from the perspective of understanding the etiology of crime, and practice from the perspective of developing effective criminal justice interventions to reduce crime. We do not attempt a comprehensive treatment of the substantial body of theoretical and empirical research on place and crime but focus instead on methodological issues in spatial statistical analyses of crime data. Special attention is given to some practical and accessible methods of exploratory data analysis that arguably should be the starting place of any empirical analysis of the relationship of place to crime. Many of the capabilities to support computerized mapping and spatial statistical analyses emerged only recently during the 1990s. The promise of using spatial data and analyses for crime control still remains to be demonstrated and depends on the nature of the relationship between crime and place. If spatial features serve as actuating factors for crime, either because of the people who or facilities that are located there, then interventions designed to alter those persons and activities might well affect crime. Alternatively, if the spatial distribution of crime is essentially random, then targeting specific places is not likely to be an effective crime control strategy. Sorting out the place/crime relationship requires analytical methods that are best suited to isolating the impacts of place on crime.

http://www.ncjrs.gov/criminal_justice2000/vol_4/04e.pdf

Summary: The purposes of this project were to determine whether patterns of burglary were communicable across diverse areas of the East Midlands (and if so, whether the pattern varied between areas) and to develop and evaluate a predictive mapping system usable in an operational policing context.

http://www.homeoffice.gov.uk/rds/pdfs07/rdsolr1907.pdf

Abstract: This research examines the relationship between demographic, social network, and criminal history variables, and the distance between the home and locations of individuals (associates) involved in an illicit drug production network. The authors integrate principals from environmental criminology and routine activities theories, journey to crime research, and social network analysis in order to explore the geographic and social space of criminal associates. The results show that the distance between individuals in the drug production criminal network and their associates vary systematically with network characteristics (centrality measures) but not with demographics or criminal history variables.

http://www.palgrave-journals.com/sj/journal/v21/n1/full/8350069a.html

Abstract: Research from property crime studies has identified a near-repeat phenomenon, where the risk of repeat burglary victimization is transmitted from a burgled location to nearby locations for a limited amount of time. This article explores the potential for near-repeat patterns to exist in another crime type, specifically the incidence of shootings. Using new tools developed to quantify the spatio-temporal patterns of near-repeat shootings within 2 weeks and one city block of previous incidents. The elevated risk of a shooting during this period is found to be 33 per cent greater than expected. It is speculated that possible reasons include coercion, retaliation, and escalation. Given that the study takes place against the backdrop of a police operation to mitigate retaliatory shootings, the potential for using this information to influence crime prevention policy is discussed.

http://www.palgrave-journals.com/sj/journal/v21/n1/full/8350068a.html

Abstract: Border control is a crucial component of national security. For a country the size of the United States, however, the length of its land borders and coastlines poses a significant security challenge. Illegal migrant workers, drug couriers, foreign terrorists, smugglers, fugitives, and other criminals benefit from the geographic range and porous nature of American borders. The purpose of this research was to identify facilitating and inhibiting factors of illegal land border crossings in order to determine physical and human geographic features related to the probability of such movement. Identifying the geographic patterns of illegal migration can help the Border Patrol optimize resource allocation and anticipate offender reactions.

http://www.palgrave-journals.com/sj/journal/v21/n1/full/8350067a.html

Summary: This article focuses on the Lafayette Colorado Police Department and their use of crime mapping. It reveals how they developed their program, their results, the financial cost, and their future with crime mapping.

http://www.theiacp.org/documents/pdfs/RCD/BigIdeasSummer2007.pdf

Abstract: Managers of public transport systems seeking to maintain or increase ridership need to be aware of the security needs of passengers on their systems. A recent review, edited by Smith and Cornish (2006), of five different types of crime and disorder on public transport looked at situational crime prevention measures currently used, or proposed for use, against these offenses. The present analysis draws on this work to present a framework for analyzing the security needs of women passengers. The discussion reviews previous research in four key areas: (1) women’s reported victimization, (2) issues related to calculating the risk of becoming a crime victim, (3) the rationality of women’s fear of crime and disorder, and (4) the need for effective and comprehensive crime prevention measures to address these security-related issues. The "whole journey" approach is used to highlight aspects of the transit journey for women passengers that require special attention among transport providers, local governmental authorities (including police departments), policy makers, and researchers.

http://www.palgrave-journals.com/sj/journal/v21/n1/full/8350071a.html

Abstract: Little is known about crime nor its spatial distribution in rural areas of the United States. The low volume of crime in these areas and problems with address reliability have likely dampened applications of crime and spatial analysis in non-urban areas. To redress that dearth, N.C. State University, in collaboration with the Western Piedmont Council of Governments and 11 county and municipal law enforcement agencies in western North Carolina, examined motor vehicle thefts using 2003 incident reports to analyze and map offenses across a four-county region. The study was able to examine the relationship of vehicle thefts to contextual and proximity to industrial areas. Further descriptive analyses of motor vehicle theft shed light on noteworthy patterns of crimes, such as trends in types of vehicles stolen, recovery patterns, and common theft locations.

http://www.ncjrs.gov/pdffiles1/nij/grants/215179.pdf

Abstract: The main goal of this project was to develop an analytical approach that will allow researchers to incorporate spatial error structures in models of rare crimes. An extension of the Generalized Cross Entropy (GCE) method was applied to the data in an attempt to utilize their flexibility in allowing error structures across space. Findings from this research confirmed that ignoring spatial structures in the regression residuals often leads to severely biased inferences and, hence, a poor foundation on which to base policy. In addition, evidence was found of homicide type-specific and areal units-specific models, highlighting the need for disaggregating violence into distinct types. However, resource deprivation in a community was found to be a reliable and persistent predictor of all types of violence analyzed and at both levels of areal aggregation. Additionally, there was evidence of a spill-over effect of resource deprivation on the amount of violence that was expected in neighboring areas. This highlights the need for taking seriously the spatial structure in a sample when planning for and implementing policy measures, especially at the intra-city level, where the observational units are spatially linked in meaningful ways.

http://www.ncjrs.gov/pdffiles1/nij/grants/205910.pdf

Abstract: Main findings indicated that victims and offenders are involved in homicide events that are relatively close to their homes. Victims had median distances of 0.06 miles and offenders 0.69 miles from their homes to the homicide events. Regardless of motive for homicide, the average distance between offender and home and victim home was always the longest. For most motives, the distance between offender home and homicide event was the next longest and victim home to homicide event was the shortest. The findings also report on person and event characteristics. Males were found to travel further to a homicide event than females, regardless of whether they were the victim or offender. Victims under 18 years of age had the shortest distance to homicide events while the opposite was the case for offenders—older offenders traveled the shortest distance to the homicide event. In terms of event characteristics, homicide events involving firearms were committed at the farthest location from the offender’s home compared to homicides committed with other weapons. The analysis focused on describing the relative distances between the victim’s home, the offender’s home, and the homicide location for the 4,552 homicides that occurred in the District during the 13-year period between 1990 and 2002. Data were gathered from the Metropolitan Police. Data analysis involved three phases: distance-to-crime analysis, explorations of spatial interactions, and explorations of cartographic representation, each of which is explained in turn. Statistical analysis included the generation of descriptive statistics on victim, offender, and event characteristics and Euclidean distance calculations on the three locations under analysis. Policy implications are discussed and include insights into how the problem solving activities of police patrol can be enhanced and how homicide investigations can be aided through an understanding of the spatial configuration of homicide events.

http://www.ilj.org/publications/SpatialConfigurationofPlaces.pdf

Abstract: Public health applications using geographic information system (GIS) technology are steadily increasing. Many of these rely on the ability to locate where people live with respect to areas of exposure from environmental contaminants. Automated geocoding is a method used to assign geographic coordinates to an individual based on their street address. This method often relies on street centerline flies as a geographic reference. Such a process introduces positional error in the geocoded point. Our study evaluated the positional error caused during automated geocoding of residential addresses and how this error varies between population densities. We also evaluated an alternative method of geocoding using residential property parcel data.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=324564

Abstract: Geocoding of address information depends on existence of geospatial data that includes features and associated attribute data relating to transportation infrastructure and either actual locations of residences (and business perhaps) portrayed as points or by polygons representing building footprints or interpolated locations of residences. In the various nations of the world, various methods for structuring this geospatial data have arisen. Some nations have highly sophisticated nationwide datasets while other nations have more rudimentary or fragmentary and inconsistent sets of GIS based addressing data. In this paper the national set of TIGER addressing data is examined along with some discussion of enhancements and local variations on the approach used in TIGER data. Then addressing datasets from Australia and Canada from the United Kingdom and other advanced western European countries and from some selected developing countries are compared with the U.S. model to examine differences and similarities in approach.

http://training.esri.com/campus/library/Bibliography/RecordDetail.cfm?ID=60643

Abstract: Vagaries associated with spatial and address data require users of geocoding software to make many quick decisions in order to create timely, accurate information. Paramount among those decisions is a method for standardizing street addresses. This paper will reveal the methods that were used to rework voter files so that ArcView GIS software’s geocoding functions could be used to help assign voters to their appropriate polling districts. Pitfalls to be avoided to improve accuracy and efficiency will also be discussed.

http://gis.esri.com/library/userconf/proc99/proceed/papers/pap623/p623.htm

Abstract: Addresses are the fundamental means by which people conceptualize location in the modern world. In a Geographic Information System, addresses are converted to features on a map via the geocoding process. Lack of standardization in addressing, differing ways of defining location, ownership and property definitions, the complexities of multi-source location and address data maintenance, differing address table schemas and models, the variety of algorithms used, and potential user error at every stop along the way are all factors that make geocoding an error-prone process. This can lead to a dilemma in view of the prevailing need of accurate geo-locating tools in our increasingly spatially aware world where the spatial representations of tabular data is becoming standard practice. This project reviews the fundamental algorithms behind the geocoding process, such as probabilistic record linkage, standardization algorithms, Soundex, and the general geocoding process within the ESRI application framework. As a case study, crime data is analyzed and processed for the City of Richardson, Texas, and solutions for the various geocoding errors are presented and geocoding base file modifications are made to accommodate site-specific needs. Programming modifications are utilized to further enhance matching capabilities. Additionally, a geocoding workflow model is proposed for municipal applications.

http://charlotte.utdallas.edu/mgis/prj_mstrs/2005/Summer/greta/Nicoara_Masters/Website/main.html

Abstract: The authors estimated accuracy and repeatability of commercial geocoding to guide vendor selection in the Life Course Socioeconomic Status, Social Context, and Cardiovascular Disease study (2001-2002). They submitted 1,032 participant addresses to vendor A twice over 9 months and measured repeatability as agreement between levels of address matching, discordance (%) between statistical tabulation areas, and median distance, and bearing between coordinates assigned on each occasion. They also submitted 75 addresses of nearby air pollution monitors to vendors A and B and then measured accuracy by comparing vendor-and US Environmental Protection Agency—assigned geocodes using the above measures. Repeatability of geocodes assigned by vendor A was high. The match rate for EPA monitor addresses was higher for vendor B versus A, but discordance at census block group, tract, and county levels also was, respectively, 1.4-, 1.9-, and 5.0-fold higher for vendor B. Moreover, coordinates assigned by vendor B were further from those assigned by the EPA. These findings suggest that match rates, repeatability, and accuracy should be used to guide vendor selection.

http://aje.oxfordjournals.org/cgi/reprint/160/10/1023

Abstract: The widespread availability of powerful tools in commercial geographic information system (GIS) software has made address geocoding a widely employed technique in spatial epidemiologic studies. The objective of this study was to determine the effect of the positional error in geocoding on the analysis of exposure to traffic-related air pollution of children at school locations. For a case study of Orange County, Florida, we determined the positional error of geocoding of school locations through comparisons with a parcel database and digital orthophotography. We used four different geocoding techniques for comparison to establish the repeatability of geocoding, and an analysis of proximity to major roads to determine bias and error in environmental exposure assessment. Results indicate that the positional error in geocoding of schools is very substantial. We found that the 95% root mean square error was 196 m using street centerlines, 306 m using TIGER roads, and 210 and 1235 m for two commercial geocoding firms. We found bias and error in proximity analysis to major roads to by unacceptably large at distances of < 500 m. Bias and error are introduced by lack of potential accuracy and lack of repeatability of geocoding of school locations. These results suggest that typical geocoding is insufficient for fine-scale analysis of school locations and more accurate alternatives need to be considered.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1964899

Abstract: Hotspot mapping is a popular analytical technique that is used to help identify where to target police and crime reduction resources. In essence, hotspot mapping is used as a basic form of crime prediction, relying on retrospective data to identify the areas of high concentrations of crime and where policing and other crime reduction resources should be deployed. A number of different mapping techniques are used for identifying hotspots of crime—point mapping, thematic mapping of geographic areas (e.g. Census areas), spatial ellipses, grid thematic mapping, and kernel density estimation (KDE), Several research studies have discussed the use of these methods for identifying hotspots of crime, usually based on their ease of use and ability to spatially interpret the location, size, shape, and orientation of clusters of crime incidents. Yet surprising, very little research has compared how hotspot mapping techniques can accurately predict where crimes will occur in the future. This research uses crime data for a period before a fixed date (that has already passed) to generate hotspot maps, and test their accuracy for predicting where crimes will occur next. Hotspot mapping accuracy is compared in relation to the mapping technique that is used to identify concentrations of crime events (thematic mapping of Census Output Areas, spatial ellipses, grid thematic mapping, and KDE) and by crime type—four crime types are compared (burglary, street crime, theft from vehicles, and theft of vehicles). The results from this research indicate that crime hotspot mapping prediction abilities differ between the different techniques and differ by crime type. KDE was the technique that consistently outperformed the others, while street crime hotspot maps were consistently better at predicting where future street crime would occur when compared to results for the hotspot maps of different crime types. The research offers the opportunity to benchmark comparative research of other techniques and other crime types, including comparisons between advanced spatial analysis techniques and prediction mapping methods. Understanding how hotspot mapping can predict spatial patterns of crime and how different mapping methods compare will help to better inform their application in practice.

http://www.palgrave-journals.com/sj/journal/v21/n1/full/8350066a.html

Abstract: Hotspot analysis helps police identify high-crime areas, types of crime being committed, and the best way to respond. This report discusses hotspot analysis techniques and software and identifies when to use each one. Researchers found that identifying hotspots requires multiple techniques, current mapping technologies have significantly improved the ability of crime analysts and researchers to understand crime patterns and victimization, and crime hotspot maps can most effectively guide police action when production of the maps is guided by crime theories (place, victim, street, or neighborhood).

http://www.ncjrs.gov/pdffiles1/nij/209393.pdf

Summary: This article describes hotspots and illustrates how to identify and analyze them using density maps and statistical tests.

http://www.ojp.usdoj.gov/nij/maps/gpsBulletin-2008v1.pdf

Abstract: Crime mapping has long been used as a tool in policing and has been adopted broadly since the advent of desktop computers made mapping dramatically easier. This article provides a brief history of crime mapping, its advantages and disadvantages, the spread of its use be American police departments, and discontinuance of its use by some departments.

http://justice.uaa.alaska.edu/FORUM/23/3fall2006/a_crimemapping.html

Abstract: Efforts to diagnose the nature and characteristics of high crime areas lead many to explore the utility of Geographic Information Systems (GIS) to study crime. However, despite the critical importance of using accurate data when identifying geographic patterns and studying hotspots, few have explored the data quality issues inherent to plotting crime events in detail. While software manufacturers provide some information about the address matching process, critical details are left out or are buried in technical, and sometimes proprietary, jargon. This paper explores these neglected details and demonstrates how the assumptions built into popular GIS software introduce bias. This close inspection of address matching is necessary as much information is lost during the interdisciplinary exchange of analytic techniques. Implications for crime analysis are discussed.

http://ccjr.csusb.edu/Reports/ECCA2004geocode.pdf

Summary: This article describes why crime mapping is useful and how smaller agencies can develop and use a crime mapping system. It also includes information on the required software, data input, and the distribution and assessment of data.

http://www.fbi.gov/publications/leb/2007/oct07leb.pdf

Abstract: The purpose of this effective practices booklet is to provide an overview of the GIS implementation process for managers and staff in small to medium size law enforcement jurisdictions. Without specifying or dictating the precise organizational and technical structure needed for implementation, this booklet seeks to establish the general managerial framework for crime mapping at the local level. It is hoped that through it managers will be able to gain a strategic vision of the purposes and administrative dimensions of GIS in law enforcement. Moreover, sections of this manual may be used as an implementation checklist for each stage of the GIS life cycle. Appendices list relevant contacts and resources.

http://www.gcc.state.nc.us/gispage/ep1.htm

Summary: This guide introduces the science of crime mapping to police officers, crime analysts, and other people interested in visualizing crime data through the medium of maps. It includes a broad approach addressing the kinds of questions crime mapping can answer and how, in general terms, it can answer them.

http://www.ncjrs.gov/html/nij/mapping/pdf.html

Abstract: The purpose of this effective practices booklet is to provide an overview of the GIS implementation process for managers and staff in small to medium size law enforcement jurisdictions. Without specifying or dictating the precise organizational and technical structure needed for implementation, this booklet seeks to establish the general managerial framework for crime mapping at the local level. It is hoped that through it managers will be able to gain a strategic vision of the purposes and administrative dimensions of GIS in law enforcement. Moreover, sections of this manual may be used as an implementation checklist for each stage of the GIS life cycle. Appendices list relevant contacts and resources.

http://www.ojp.usdoj.gov/nij/maps/gpsBulletin-2008v1.pdf

Summary: This article describes how to create maps and how GIS is used in law enforcement. It also lists various training and other resources.

http://www.ojp.usdoj.gov/ovc/publications/infores/geoinfosys2003/191877.pdf

Abstract: There is ample evidence that problem analysis that includes mapping is an effective means of directing police activities. However, this evidence tends to be both problem- and site-specific. While computerized crime mapping might help an agency to deal with some specific problems, such as robbery, loitering, vandalism, and drug sales, there is little information on how the technology (and proactive approach) affects the organization. Specific problems are well-known threats. New technology, decentralized decision making, openness with the community, taking responsibility for prevention, and other changes associated with data-driven management are today’s demons. To encourage the use of mapping, one must first encourage a proactive and preventive approach to policing. Relatively few law enforcement agencies use computerized mapping, and fewer still are taking advantage of its full potential. There are two reasons for this. First, the computerized mapping, as a relatively recent law enforcement development, is in an early stage of the innovation cycle. The diffusion of innovation takes some time with the spread proceeding slowly at first. Second, the computerized crime mapping, despite its potential, remains a largely unexplored area that may present unforeseen problems for law enforcement agencies and executives.

http://www.policefoundation.org/pdf/mappinginpoliceagencies.pdf

Summary: The theme of this issue of Crime Mapping News is regional (cross-jurisdictional) data sharing and crime mapping. Law enforcement practitioners and researchers have long been aware of the fact that crime patterns and criminal activity are not limited by city, county, or even state boundaries. Therefore, the development of partnerships to enhance information sharing across jurisdictional boundaries is essential to effective crime analysis and crime mapping efforts. The articles in this issue cover topics including 1) a statewide crime analysis and mapping project among police agencies in Massachusetts that use NIBRS reporting guidelines, 2) a data exchange and regional crime mapping initiative in Sussex, UK, and 3) an example of a proposal for a multi-jurisdictional crime mapping initiative sponsored by police departments and other government agencies in the metropolitan Kansas City area.

http://www.cops.usdoj.gov/files/RIC/Publications/v2_i3_summer00.pdf

Abstract: Over the last decade, crime mapping has emerged as one of the most important and popular innovations in American policing. Computerized crime mapping has become a standard tool in American police agencies. With recent improvements in mapping software, mapping crime across borders and giving police managers the capabilities to see larger crime patterns are becoming more of a reality. However, mapping across jurisdictions has emerged as a major problem in the integration of crime mapping into police problem solving. Crime problems often cross jurisdictional boundaries. But crime analysis is often based within specific jurisdictions, and police agencies have found it difficult to move from the idea of cross-jurisdictional crime mapping to actual implementation of systems for examining crime across jurisdictional boundaries. In this, the police have faced not only technical, but also organizational, political, and social barriers. This paper discusses factors that influence the utility of creating a Cross Boundary Crime Mapping System (CBCMS), including the willingness to act on discovered patterns, the presence of shared crime patterns, data quality, administrative arrangements, and concerns about privacy and data sharing. Although technology has made cross-jurisdictional mapping possible, these issues are the most critical to success.

http://www.policefoundation.org/pdf/barriers-eck-2002.pdf

Abstract: Geographic information systems are a new and powerful technology that can enhance the ability of researchers and practitioners to identify problem areas and target scarce resources more efficiently. GIS also enable greater data-sharing capabilities within and among agencies and organizations, resulting in greater access by many to vast amounts of data. This report is designed to provide guidance to law enforcement personnel, researchers, and others who are creating and sharing crime maps. It contains real-life examples and illustrations contributed by various police departments that demonstrate a variety of techniques that promote privacy, crime mapping, and data confidentiality.

http://www.ncjrs.gov/pdffiles1/nij/188739.pdf