ArcView GIS, MapObjects Professional, and MapObjects IMS 

Philadelphia Police Go Online to Fight Crime

ScreenshotThe Philadelphia Police Department (PPD) handles about three million 911 calls annually-a workload that could prove overwhelming to a limited staff. To help with its management, the PPD relies on a sophisticated geographical database to generate up-to-date maps for use in crime analysis.

September 1997 marked the official launch of the Crime Analysis and Mapping Unit of the PPD. Small though it may be--three civilians and one officer--it serves the needs of 7,000 police officers and 1,000 civilian personnel. Since 1992, the City of Philadelphia has made great strides in developing a GIS infrastructure that today is the largest distributed, integrated municipal GIS in the country.

Putting the Maps to Work

Along with producing maps using ESRI's ArcView GIS Version 3.1, the crime unit provides input on the analysis of patterns in the data with the help of ArcView Spatial Analyst. The PPD holds crime analysis meetings on a rotating weekly schedule with two to three divisions scheduled per week and all nine divisions covered over one month. The maps include sheets for homicide, aggravated assault, property crimes, vehicle-related crimes, rapes, robberies, and narcotics. The Crime Analysis and Mapping Unit, which is staffed by GIS programmer/analysts Lorlene Hoyt, Robert Cheetham, and Kevin Switala, and officer Joe Blickley, also produces maps for special requests such as gunshot incident density and recent criminal activity for helicopter crews.

Within a few months after the system's implementation, the PPD was seeing a difference. The maps played a part in the PPD's locating and busting vehicle "chop shops," where stolen cars are dismantled and sold for parts. Another benefit came as high crime patterns were identified on the maps; police patrols were realigned to fit the need. 

Robert Cheetham and Kevin Switala, both GIS programmer/analysts for the unit, have been working on developing more applications for the crime unit. Switala developed a stolen vehicle tracking application that enables officers to see the location of recovered vehicles in relation to the area in which they were stolen. 

The crime unit is taking its endeavors several steps furtherThe crime analysis unit has begun to use ArcView Spatial Analyst to observe crime densities. This application proved particularly useful in breaking a large drug enforcement case. Street maps showing building footprints and crime densities have enabled the PPD to do more effective planning in the operation. Cheetham says, "They didn't realize how bad crime was in some areas until they saw the patterns on the density maps."

Continuing to develop applications, the crime unit is taking its endeavors several steps further with the objective of automating the map production process and enabling personnel within each of the PPD's districts to map results of ad hoc queries.

Cheetham and Switala were well aware of how their efforts were benefiting the PPD, but they also knew that the sheer volume of events had the potential to slow down the map production process. They envisioned a plan to decentralize the mapping functions to each of the district offices, enabling any officer or detective to generate customized maps.

"What the officers are really interested in is getting more timely maps. We already produce a lot of maps in hard copy that are sent out, but they want to get more-they want to see patterns faster," says Cheetham. "The more information officers have, the better equipped they are to do their job."

Cheetham and Switala decided to work with ESRI's MapObjects Professional, which can be used with common desktop software in each of the district offices, and began constructing incident query forms using Visual Basic applications to integrate into MapObjects Professional.

The generic incident mapping application they designed will enable officers to define a series of parameters on a form, submit the request, and have a map of incidents returned. Identification requests will return multiple incidents and show related arrest information.

Cheetham says, "The decision to go with MapObjects was not just a software choice. The entire component software approach has allowed us to rapidly construct several small, focused applications with customized interfaces and capabilities outside that of ArcView GIS."

Application Distribution

With the applications construction issue dealt with, they were still left with the problem of distribution. Although MapObjects Professional does not require the system and hardware resources necessary to run ArcView GIS, it does require a 32-bit Windows operating system and the PPD is standardized on Windows 3.1. Unless workstations were upgraded to Windows 95 or NT, the MapObjects Professional applications couldn't be installed in the district offices. A Windows NT infrastructure is being phased in, but the crime analysis and mapping group was concerned about the potential systems administration burden when the mapping applications were installed in the district offices.

MapObjects Internet Map Server responded to this concern with its ability to serve dynamic maps and data quickly on a variety of servers. Using the MapObjects IMS solution, the crime unit will be able to serve multiple applications from a single server to any number of clients. It also centralizes the administration of both data and applications and can easily accommodate expansion of the system as the number of clients rises.

Officers will be able to access several reports including summaries of activity for a user-specified period, lists of incidents occurring at a single address, and charts analyzing day-of-week and time-of-day relationships for aggravated assaults and robberies. Another benefit of the Intranet-based applications will be the team's ability to turn around late-breaking information immediately.

Cheetham and Switala have deployed the general mapping and analysis tools in a pilot program with good results, and they anticipate January 1, 1999, as the City-wide rollout.

For more information contact Robert Cheetham (tel.: 215-686-1198, fax: 215-686-3337, or E-mail: cheetham@pobox.upenn.edu).