Ancient history: Cartography and crime mapping|
Chapter 1: Context and Concepts
Conclusive evidence from clay tablets found in Iraq proves that maps have
been around for several thousand yearsperhaps tens of millennia (Campbell, 1993). Evidently, the need to display
geographic data is basic and enduring. Nowhere is the need for maps more compelling than in the field of navigation, whether for an epic around-the-world voyage or for a rookie cop's struggle to find an address in a city map book. Maps for navigation can be matters of life and death, and the inability of early navigators to locate themselves accurately on the surface of the Earth have often spelled disaster, as described vividly in Dava Sobel's book Longitude (1995).
Fortunately, crime mappers do not have
to be concerned about such epic matters. However, mapping crime is a scientific activityan application of the broader
scientific field of cartography, which has undergone a transformation with the advent of geographic information systems (GIS). Many mapmakers now see cartography as a branch of information technology. A decade or so ago, cartography was much broader in scope than GIS with applications in fields as diverse as surveying, navigation of all kinds (including
orienteering and highway mapping),
geology, space exploration, environmental management, tourism, and urban planning. Today, however, the convergence
of cartography and GIS is nearly complete. Both are tools in a broad range of applications, reflecting the most important use of mapsto communicate information.
Crime mapping, as noted at the beginning of this chapter, has quite a long history. Phillips (1972) pointed out that "hundreds of spatially oriented studies of crime and delinquency have been written by sociologists and criminologists since about 1830. . ." and recognized three major schools:
The social ecologists recognized and classified areas in cities with similar social characteristics. Shaw and McKay (1942) produced a classic analysis on juvenile delinquency in Chicago. This work is generally recognized as the landmark piece of research involving crime mapping in the first half of the 20th century. Shaw and McKay mapped thousands of incidents
of juvenile delinquency and analyzed
relationships between delinquency and various social conditions. Work by the "Chicago school" of researchers also delineated an urban model based on concentric zones, the first attempt to develop a theory to explain the layout of cities (Burgess, 1925). Other significant contributors to the ecological school included Lander (1954), Lottier (1938), and Boggs (1966).
- The cartographic or geographic school dominated between 1830 and 1880, starting in France and spreading to England. This work was based on social data, which governments were beginning to gather. Findings tended
to center on the influence of variables such as wealth and population density on levels of crime.
- The typological school dominated between the cartographic period and the ecological period that would follow in the 20th century. The typologists focused on the relationship between the mental and physical characteristics of people and crime.
- The social ecology school concentrated on geographic variations in social conditions under the assumption that they were related to patterns of crime.
Most likely, the first use of computerized crime mapping in applied crime analysis occurred in the mid-1960s in St. Louis (McEwen and Research Management Associates, Inc., 1966; Pauly, McEwen, and Finch, 1967; Carnaghi and McEwen, 1970; for more discussion, see chapter 4). Ironically, professional geographers were late getting into the act. Early contributions came from Lloyd Haring (who organized a seminar on the geography
of crime at Arizona State University around 1970), David Herbert in the United Kingdom, Harries (1971, 1973, 1974), Phillips (1972), Pyle et al. (1974), Lee and Egan (1972), Rengert (1975), Capone and Nichols (1976), and others. Among the most remarkable (and little known) pieces of research emphasizing crime mapping were Schmid and Schmid's Crime in the State of Washington (1972) and Frisbie et al.'s Crime in Minneapolis: Proposals for Prevention (1997)(figures 1.3 and 1.4). The latter, in particular, was notable for bridging the gap between academic crime mapping and analysis/applications specifically aimed at crime prevention. Early computer mapping efforts used line printers as their display devices, so their resolution was limited to the physical size of the print characters. This precluded the use of computer maps for the representation of point data, at least until plotters that were able to draw finer lines and point symbols came into more general use. (For an excellent review of early map applications in crime prevention, see Weisburd and McEwen, 1997, pp. 1-26.)
Even as late as 1980, the breakthrough into widespread GIS-style crime mapping was about a decade away. It was necessary to wait for improvements in desktop computer capacity, printer enhancements, and price reductions before desktop mapping could become an everyday, broadly accepted phenomenon.
To illustrate how matters have improved, a snippet of personal history is offered.
In April 1984, the author bought his first personal computer, a Kaypro 10 manufactured by Digital Research, Inc. This
wonder ran at 4 megahertz and had
64 kilobytes of random access memory (RAM) and a 10-megabyte hard drive. ("How could you ever use all that storage?" friends asked.) It also had a tiny monochrome display and ran on the
CP/M operating system, the precursor of Microsoft DOS. And all this for the rock-bottom price of $2,795 in 1984 dollars. The Silver Reed daisy wheel printer purchased to complement the computer was $895 (extra daisy wheels were $22.50 each, tractor feed for paper was $160), and the 300k-baud rate modem was $535. After adding a few other knickknacks, getting started in personal computing cost almost $5,000 (again, in 1984 dollars).
By comparison, the typical RAM in
1999 is perhaps 1,000 times larger (64 megabytes), the processor speed is 100 times faster (at least 400 megahertz), and hard drives routinely are 100 times bigger (10 gigabytes), all at a lower price. It was this type of computing environment that would facilitate the entry of GIS into law enforcement (and elsewhere) and permit cartographic principles and practices to be used on a day-to-day basis. Mapping crime has come into its own primarily because of advances in computing that,
in turn, have facilitated GIS applications. Apart from all the obvious advantages, a major benefit is that computer mapping allows free rein to experiment, a luxury denied in the old days of manual mapping. Are you wondering what a certain map design would look like? Try it out. You don't like it? Start over and have a new map in minutes.