ArcNews Online

Spring 2010

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Online Only Article High-Tech Crime Mapping Helps Protect the City of Brotherly Love

Philadelphia Police Use a Myriad of GIS Tools


  • The PPD can access more than 150 geographic data layers.
  • The GIS allows sophisticated data mining to extract information from large transactional databases.
  • A GIS-enabled crime search lets officers enter police report information into a form that can be viewed by others through the intranet.

Philadelphia, Pennsylvania, is a city of historic events, such as the drafting of the U.S. Constitution, and attractions, such as the Liberty Bell. But the geography of the city comprises more than a maze of national historic sites. Philadelphia, like many metropolises, is a tangled web of districts, neighborhoods, streets, buildings, and homes.

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This is an example of the stolen/recov auto intranet Web application. This shows where cars were stolen (red dots) in relation to where they were recovered (blue squares). Police personnel can quickly see if there are hot spots and clusters of where cars are being recovered through the dynamic linking.

Serving this complex city is the Philadelphia Police Department (PPD), the nation's fourth largest police department, with more than 6,600 officers and 800 civilian personnel and covering more than 40 square miles in which approximately 1.5 million people reside.

For PPD, 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.

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This is a closer zoomed in look of the same example as above.

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

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

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This is a screen capture of the PPD ArcMap 9.3 project that its displays at its CompSTAT meetings. This example shows residential burglaries that have occurred over the last week (purple), over the last 28 days (red) and the previous 28 days (gray). Additionally, burglars recently released as well as people with active warrants in the area for burglaries are displayed. The blue polygon outlines represent current footbeat patrols in this given police district.

Special units served by the Crime Analysis and Mapping Unit include homicide, narcotics, major crimes, highway patrol, and crime scene. 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.

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 is also captured for incidents involving shootings and gun arrests and seizures.

The unit currently has several GIS applications available to police personnel from any desktop or laptop computer via the department's intranet Web site. 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 the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF); then receives the electronic response and enables mapping and analysis of the results
  • Spike Detector—A specialized data mining solution for automatically detecting statistically significant changes in clusters of incident events and notifying officers and command staff about them

One of the more advanced uses of GIS involves sophisticated data mining techniques to extract useful information from large transactional databases. The 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 members can quickly view the map to understand where crime is occurring with greater frequency.

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This is the Spike Detector application. This map is interactive. Users can click on any of the red squares and drill down into the raw graphs, maps and tables that make up that given spike. This example shows all the recent spikes around the city for stolen autos.

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 for Greater Agency-Wide Effectiveness

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, then 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.

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This is one of the screens a user can go to after clicking one of the red squares above on the interactive stolen auto spike map. Users can clearly see how this is a spike when compared to similar time periods going back in time for that same particular catchment area. The black bar at the end of the graph represents the spike in stolen autos. The graph is interactive as well. Users can click any one of the bars and drill down into the tabular data and then go to a map to see the geocoded points within that catchment that make up the spike alert.

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 Michael Urciuoli, GIS specialist, Philadelphia Police Department. "GIS functionality provides a spatial component to visualize suspect data and link crime data by geography."

A GIS-enabled 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.

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 still maintained by Esri Business Partner Azavea ( (previously Avencia Incorporated). 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."

More Information

For more information, contact Michael Urciuoli, GIS specialist, Philadelphia Police Department (e-mail:

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