• The forward extension of current trends.

• Pure speculation, with the likelihood that some ideas will become reality while others will fade away.

Clarke also noted that data will become more complete, more detailed, more timely, and more varied than ever before. This will be helpful to GIS as an "end user" of data—if the core data get richer, then possibilities for enhanced analysis also increase. But Clarke was referring to GIS in general. Can we have the same expectations for crime mapping?

Given that most crime data are already point defined (address-type), could they be improved in terms of spatial definition? Yes, at least marginally, through the use of GPS technology to remove address ambiguities, of which there are many. Whether locational data can be improved across the board may depend on the GPS protocols that develop, one police department at a time. Data quality will probably improve, and addresses will probably become more precise as more agencies use automated field reporting and integrated computer-assisted dispatching and records management systems.

More on GPS and policing

Equipping patrol units with GPS would mean that their locations could be known as often as each unit is "polled," or automatically asked to respond, perhaps every few minutes. This would be an excellent security device for officers, since their location could be determined at any time, and, if an officer were down or needed help, knowing his or her location would save valuable time.

But will GPS units typically be located in patrol cars? If so, some ambiguities in incident location will remain, since the car will not always be parked precisely where the incident takes place. If GPS units are hand held, or incorporated into officers' uniforms, accuracy may improve significantly. The caveat on GPS data, however, is that the physical environment may not permit a satellite reading owing to the presence of tall buildings or other obstacles. Such difficulties aside, the era of real-time access to spatially enabled crime data is rapidly approaching—a development that will force us to reconsider what we are doing and why and how we are doing it. This development is not without risks, such as the temptation to jump to premature conclusions on the basis of real-time, but possibly unconfirmed, information.

The Web: Already a force in the dissemination of police information

A development that may have the greatest impact on the manipulation of crime data may be the use of the Web for access to data that have already been geocoded and are in the public domain, such as census data, including census geography. A corollary development will likely be demands for local data on Web sites. Currently, police departments are split on this issue, with some routinely putting their less sensitive data on the Web, and others refraining from doing so. The power of the Web to facilitate data sharing will invite more open data dissemination protocols, but these will be offset to some extent by security and privacy concerns.

Public information revisited: How much public access to allow

A pervasive force at work in the background is the historical culture of policing that has generally frowned on easy public access to crime data. This reluctance is borne of several factors, including fear of misuse and misinterpretation; the indisputable need for confidentiality for some crimes, such as rape and juvenile offenses; fear of political reprisals when crime rates are increasing; and a reluctance to expend scarce resources on data dissemination. In the background was, and is, a certain degree of proprietorship regarding data and a somewhat natural reluctance to simply give information away, even though it might be in the public domain already, at least in theory. A subtext to this is the view that crime data should not be made available to the public if they do not have to be, since public disclosure only constitutes another potential source of problems.

On the other hand, undermining nondisclosure is the fact that many city and neighborhood newspapers routinely publish lists of local crimes, complete with addresses. The only missing link is the codification necessary to produce a citywide map. Criminal matters most often come before the courts and, in so doing, jump squarely into the public domain. In the long term, it is increasingly difficult to see how most crime data could be kept private, particularly data related to incidents for which there is no active investigative interest and no need to protect victims. Indeed, some departments that were secretive a decade ago are now beginning to put their data out on CD-ROMs or at least are talking about doing so. Others refuse to release data, even for legitimate apolitical research.

One certainty is that, in addition to technological and methodological innovations in crime mapping and in collateral fields that can be productively integrated into mapping methods, a debate about the disclosure and exposure of crime data will continue into the foreseeable future.

Multimedia and integration