Predictive Modeling Becomes a Crime-Fighting Asset

Economic downturns don't just affect businesses. Government agencies have to do more with less as budgets get trimmed and tax revenues slow to a trickle. This can be especially difficult for law enforcement where public service means fighting crime and protecting lives.

For the Philadelphia Police Department (PPD), geographic information system (GIS) software provides an invaluable resource for meeting mission demands. The enterprise platform provides commanders and frontline staff with the ability to make sense of millions of historic incident records to accurately pinpoint crime rates and patterns. Instead of dozens of individuals combing through thousands of pages of paper documents or volumes of spreadsheets and digital forms stored in multiple locations, PPD uses GIS to unlock its data stores and make better decisions. In addition, the PPD GIS allows officers of any rank and in any department to perform their own information analysis. They can quickly and easily perform a query, see the results and share it with other staff.

GIS gives PPD an information-based resource for strategically placing field personnel and executing policing programs that deter crime, apprehend suspects and quickly respond to emergencies. Information flows throughout the organization. The agency proactively stays ahead of the crime-fighting curve.

Crime Analysis & Mapping Unit
The Philadelphia Police Department is composed of more than 6,600 officers, approximately 405 patrol cars, 116 emergency wagons and numerous auxiliary vehicles for police use. The Crime Analysis and Mapping Unit was established in September 1997 as part of a block grant from the National Institute of Justice (NIJ). This grant provided the agency with the resources to implement GIS as part of a comprehensive information technology architecture.

Today, PPD uses ESRI ArcGIS 9.3 software, Microsoft Visual Studio, Microsoft Access 2002 and Microsoft SQL Server 8.0.

The unit consists of three civilian GIS professionals. GIS accesses the department s incident database (INCT), which stores every crime reported since July 1997. These records are generated from 9-1-1 calls. Crime addresses from INCT files are mapped to a city street file as a dot, a process called geocoding. The GIS can access more than 150 geographic data layers, with more than 50 of these maintained by the unit. The unit geocodes more than 5,000 incidents each day and nearly 2.5 million incidents annually. The geocoded incidents have specific symbols based on crime type.

The types of services include printed maps, database reports, statistical graphs and charts, and intranet mapping services.Ad hoc requests are also done. The unit produces as many as 50 maps a week. This can include regularly updated incident maps, such as weekly or monthly maps showing crime density, locations, police beats, arrests, calls for service, citations issued and car accidents. Points of interest are also mapped, such as liquor-licensed establishments, surveillance camera locations, hospitals, nightclubs, shelters and halfway houses. In addition, data on buildings, railways, sidewalks, alleys and open areas is integrated into the GIS.

Special units served by the Crime Analysis and Mapping Unit include homicide, narcotics, major crimes, highway patrol and the Crime Scene Unit. The Mapping Unit also serves the district attorney's office for court preparation by frequently providing court maps. Staff can fill out an online request, phone in a request or go to the unit in person to ask for a map product.

Geo-enabled COMPSTAT
Senior ranking officials attend weekly computer statistics (COMPSTAT) meetings held at agency headquarters to review recent events, share work activities for each police district and jointly plan future policing programs.

Crime in each police district is broken down by type and further analyzed to identify the place of occurrence as well as the time of day, day of the week, and week and month of the year. Homicides, rapes, robberies and aggravated assaults are divided into incidents committed with and without guns. Aggravated assaults are further classified as domestic or nondomestic. Burglaries are listed as residential or commercial. Thefts are classified as retail theft, theft from a person, theft from an auto and auto theft. Data are also captured for incidents involving shootings and gun arrests and seizures.

The custom ArcGIS Desktop map displayed at the meetings shows crimes that have occurred not only over the last 28 days but also the previous 28 days. Commanders assess the impact and effectiveness of anticrime strategies. Drug arrest patterns are mapped with other crime data, because narcotics often spur violent crime. District maps display narcotics arrests of both buyers and sellers along with reported crime. In addition, recent prison releases and active arrest warrants can be overlaid on top of individual crime types. This helps police visualize and generate potential suspects to target in an area that is clustered with a specific crime type.

We analyze patterns of different crime types, what times they are occurring, and what days they are occurring, then produce density maps and hot-spot maps to decide how to best deploy personnel, says Michael Urciuoli, GIS specialist, Philadelphia Police Department.

A GIS-Based Intranet Hub
The unit currently has several GIS applications available to police personnel from any desktop or laptop computer via the department's intranet. They consist of three major components:

  • PhiCAMS Web-based crime mapping software that supports analysis with tables, statistics, charts, and maps for incidents, arrests, and other datasets;
  • Firearms Analysis System (FAS) A firearms system that accepts firearms trace requests from detectives; transmits an electronic request to Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF); then receives the electronic response and enables mapping and analysis of the results; and
  • Spike Detector A specialized data mining solution for automatically detecting statistically significant changes in clusters of incident events and then notifying officers and command staff about a newly detected cluster.

The PhiCAMS application allows officers at the district level to enter specific parameters dates, crime codes, and suspect and district information as a query and search results as a map view. Clicking the resulting mapped locations (e.g., a car theft) accesses tabular information, such as the incident police report, stored in the department s records management system.

For instance, an officer can request a list of car thefts between Friday and Monday of the first week of the month during the hours between midnight and 6 a.m. within a six-mile radius of a given address. Instantly, a digital map will appear, displaying the results. Clicking the incident icon on the map pulls up specific incident data, such as the responding officer, type of vehicle stolen and additional information the vehicle s owner might have provided. Graphs and charts show such information as the number of burglaries by month over a year or the percentage of major crimes by type including assaults.

The FAS application was constructed as part of a gun-tracking initiative funded by the Pennsylvania Commission on Crime and Delinquency (PCCD. The intent of the application was to reduce the amount of redundant data entry related to firearms, increase data transfer speed between agencies, and provide data analysis and visualization tools via secure intranet applications. It is also a system built to assist the PPD and the ATF in collecting information pertaining to firearms more accurately and efficiently.

PPD officers use interactive maps to locate guns seized in a particular period of time; trace the pathway of a firearm across the country from manufacture to use in a crime; link maps of a suspect s residence to crime locations; and produce thematic maps by manufacturer, importer, caliber, type, and crime class. Since its use in production, the FAS has cataloged and transmitted 5,000 firearms per year, dramatically increasing the speed with which trace results are returned to the officers requesting them and providing an important intelligence resource for both the PPD and the ATF.

One of the more advanced uses of GIS involves sophisticated data mining techniques to extract useful information from large transactional databases. Staff performs hot-spot assessments where the relative density of incidents is examined and mapped using color-coded references to indicate high or low incident concentrations. Staff can quickly view the map to understand where crime is occurring with greater frequency.

The crime tracking solution, known as Spike Detector, is an early warning system that puts crime parameters in place, and any deviation from the user-defined crime pattern is instantly and automatically sent to officials via an e-mail alert. The solution integrates incident information with location data, such as proximity of crime type to police units and facilities, as well as temporal data.

GIS software is used daily to comb through millions of records and search for recent, geographically clustered crime frequencies. The system automatically alerts police captains by e-mail when crime spikes occur and provides location and attribute data. Commanders view digital information-packed crime maps along with lists of reports and related incident information. Instant notification means management officials receive accurate and timely intelligence when it s available; they can then more rapidly deploy response tactics and follow up and assess results.

Additional Applications
The unit has also created a public school incident data application that supplies the most current information on crimes occurring within the public schools of Philadelphia in an intranet tabular format.

The agency's stolen/recovered vehicle tracking application displays links between where vehicles are stolen and their recovery locations. A map depicts the location of a stolen vehicle and where it is recovered, and a line connecting the two points is overlaid on city street data. This type of analysis and information helps agents see exactly where and when to increase policing efforts and to track down potential chop shops where stolen vehicles are taken.

A user can also access prisoner release information, such as the person s arrest record and current address as well as a photo ID. A simple query can locate where the released prisoner resides.

The same type of query can be done for persons wanted for various crimes throughout the city. In addition to a map depicting a suspect s last known address, the location of the incident, warrant information, and suspect information and picture ID, other details are also available.

The map serves as an intuitive interface to access data, says Urciuoli. GIS functionality provides a spatial component to visualize suspect data and link crime data by geography.

A GIS-enabled Part 1 crime search lets officers enter police report information into a form that can be viewed by others through the intranet. The user can search any number of fields in the form. The user can also specify a phrase or word throughout any field or narrative in the report. The form has a large number of fields for entering crime information for an incident.

This has proved to be particularly effective when looking for patterns or similar methods, says Urciuoli. You can enter silver handgun as a phrase search, and it will pull up records on any Part 1 crime where the phrase is listed. Now the officer can print out all recent crime report forms where a silver handgun was used and possibly piece together patterns and similar crimes. What once involved putting in a request for someone else to process a report is now done by anyone who wants the results instantly.

Recently, all these intranet applications have been made available to all mobile data computers (MDC) in every patrol vehicle. This has enabled police personnel to perform analysis and data mining in the office as well as in their vehicle.

PPD recently unveiled a public Web site where city residents can map the incidence of major crimes in Philadelphia. The site uses existing GIS software and data to provide the external city Web site ( with crime information. Both the public site and the intranet mapping site were developed and are maintained by Avencia ( The site provides citizens with a simple, accurate map display of crime across the city. Data is updated nightly from police department databases. A month s worth of crime data can be viewed and downloaded.

GIS is changing the way we operate, says Urciuoli. All police personnel, from the police commissioner down to the officer in the patrol car, can use maps as part of their daily work. Our online mapping applications needed to be fast and user-friendly because police officers don't have time to become computer experts. I think we've delivered on this goal, and it's transforming what we do and how we serve the community.


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