Synthesis 2000
Chapter 5: Synthesis and Applications

What are the most obvious characteristics of crime mapping at the beginning of the new millennium? Several come to mind:

Technology imbalance—most police departments, except large ones (more than 100 sworn officers), do not use crime mapping technology.

Urban, suburban, and rural differences—in terms of crime analysis and mapping, the perspectives and needs of urban, suburban, and rural police departments greatly differ.

Incomplete geocoding—efforts to geocode rural addresses are under way.

Geographic information system (GIS) functions—GIS is used for descriptive, analytical, and interactive purposes.

GIS mapping—GIS is used to represent information in the form of points, areas (polygons), and lines.

Decreasing costs—more capabilities become available as the cost of mapping technology declines.

Crossjurisdiction alliances—these relationships recognize that criminal behavior pays little heed to departmental boundaries.

Theory and practice—the link remains weak.

Data sharing—collaboration among State and local agencies is becoming more common.

Context—the "backdrop" is increasingly being recognized as critical to understanding crime patterns and crime prevention.

Privacy issues—these issues become more urgent as the ability of law enforcement agencies (and others) to link information to addresses and individuals increases.

Public access—access to geographic information increases with the use of the Web and systems such as ICAM (Information Collection for Automated Mapping) in Chicago.

Let's consider each point in turn.

Technology imbalance. Why are most police departments not using computerized crime mapping? (Only 13 percent reported using the technology in the 1997-98 survey by Mamalian and La Vigne et al., 1999.) Part of the answer lies in the very different needs and capabilities of urban, suburban, and rural law enforcement agencies. The needs and resources of large urban departments make computer crime mapping practical. Crime rates, particularly in so-called inner cities with larger police departments, are generally higher than in suburban or rural areas. A larger police force also means that tasks can be more specialized and that the probability of having a staff dedicated to crime analysis is greater. The political map is extremely fragmented in some areas, such as Los Angeles and Chicago, with numerous small, incorporated communities outside the central city. While the total population in such metropolitan areas may be large and the crime problems significant, political fragmentation decreases the likelihood that police departments are, individually, able to deploy specialized crime analysis units.

Urban, suburban, and rural differences. Reasons for variations in the use of automated mapping go beyond the size of police departments and questions of labor force specialization. Urban, suburban, and rural environments differ fundamentally in a number of ways that relate to the distribution of crime (Mazerolle, Bellucci, and Gajewski, 1997). Among the obvious differences are those relating to population density, racial and ethnic diversity, social cohesion, and economic health. Higher population density means more potential for crime in a given area. This does not necessarily mean higher crime rates, however. A rural county may have a higher population-based crime rate compared with a city, but the city has more crimes due to its having a larger population.

Urban law enforcement differs markedly from that in rural areas, where communities and residences may be widely separated. Rural policing may be just as fragmented as urban policing. Each small town may have its own police department with a handful of officers, while the surrounding area may be the responsibility of the sheriff or State police. (To add to the confusion, in large cities sheriffs are not necessarily involved in street-level criminal law enforcement but may act as officers of the court, dealing with court orders, evictions, repossessions, and, perhaps, jail administration.)

Paradoxically, perhaps, response times to calls for service (CFS) for the responsible agency in a low-density rural area may be much longer than from its neighbor, depending on the locations of police facilities. Concepts like patrol that are the bedrock of urban and suburban law enforcement mean little in an environment like that illustrated in figure 5.1. Response time, too, must be thought about differently. It is easy to overlook law enforcement environments that are nonmetropolitan, since the problems that attract most attention are in urban locations, as are the media. Furthermore, the literature on GIS in policing is almost exclusively dedicated to urban case studies. Because the application of GIS to low- density suburbs and rural environments is a new frontier and has been extremely limited, hard questions need to be asked: Does rural law enforcement really need computer mapping? Can GIS improve rural policing?

Figure 5.1

Incomplete geocoding. Historically, geocoding efforts have had a distinctly urban bias, for obvious reasons. The majority of people lived in the cities, and the census enshrined urban geocoding by linking early address matching initiatives to the areas that we know today as Metropolitan Areas. Rural areas were essentially impossible to geocode because their rural route and post office (P.O.) box addresses inhibited the construction of links to the locations of housing units or businesses. Preparations for Census 2000 include an aggressive effort to geocode rural addresses. In some cases, 911 street addresses are already available (typically in the rural parts of metropolitan counties). In other cases, field workers go out and record the locations of structures and reconcile them to their rural route or P.O. box number, if possible. This effort is essentially a cooperative venture among local governments, the U.S. Census Bureau and the U.S. Postal Service.1

Figure 5.2

Figure 5.3

Figure 5.4

GIS functions. The uses of GIS in policing can be characterized as descriptive, analytical, and interactive. Descriptive maps can be equated with traditional cartography in that they tend to be a static picture of information, albeit a very useful one, as exemplified by the styles shown in figures 5.2, 5.3, and 5.4. Descriptive is not a pejorative term—it is the foundation of scientific investigation. Accurate description is an extremely valuable commodity easily capable of providing answers to questions. Accurate and timely description is the foundation on which GIS rests. Analytical maps go a step further and consider relationships among map elements or use methods based on spatial statistics software, such as STAC (Spatial and Temporal Analysis of Crime) or the ArcView Spatial Analyst. In interactive mapping, the analyst enters and changes map parameters "on the fly," perhaps testing theories about fluctuating drug-market boundaries, studying the displacement effects of a crackdown, or examining how buffering features may affect outcomes. (For examples of analytical maps, see figures 5.7 and 5.9. For an example of what was originally an interactive animated map, see figure 6.8.)

Chapter 5: Synthesis and Applications
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Mapping Crime: Principle and Practice, by Keith Harries, Ph.D., December 1999