With a homicide rate leading the nation, the city of Chicago is testing new methods for targeting gang and drug hot spots. Using the recently christened Deployment Operations Center (DOC), the Chicago Police Department (CPD) is serving current crime data and analyses to its Intranet with GIS technology. The DOC Web site serves as a clearinghouse for data specifically related to homicide and aggravated batteries with firearms, integrating these map layers with research on gang-related activities. Presenting this information in its geographic context is allowing officers to make better informed decisions about which areas are in need of additional manpower.

As virtually every operational activity in law enforcement includes spatial relationships, using GIS to illuminate interactions and patterns buried in the data is critical. Serving these capabilities to an Intranet adds even more power, supporting either specific or multipurpose applications.

"With the Web site, officers are able to quickly place where these deployment areas are located," says GIS manager Joseph Kezon. "We have also added links to PDFs with descriptions of why an area was chosen by members of DOC. For example, we are looking for this gang member; these are the cars involved; these are the aggravated batteries with a firearm and homicides that occurred in the past seven days; and here are the number of calls for service, shots fired, and so on."

Steve Caluris, commander of DOC, has been a longtime user of Esri technology and was instrumental in the decision to have the Web site created. Commander Caluris holds weekly briefings with the command staff to discuss and explain the updated deployment areas. In addition, he holds daily briefings with the superintendent of police and his staff regarding major incidents over the previous 24 hours. A Web site hosts the major incident log and allows users to get an up-to-date view of major incidents that have occurred. Maps are also handed out at the briefings.

The DOC Web site is an example of a specialized application created to meet a specific need. However, CPD built this site on the solid base of departmentwide ArcIMS capability. The department has been a user of Esri technology for years. Its first public Web site for crime mapping was based on MapObjects technology. Today, the ability to serve maps and live data to its Intranet is a tremendous resource for officers throughout CPD, and with a database containing close to 18 million records, the ability to leverage all available information is critical. Although the department had used various methods of data sharing in the past, keeping these map layers up-to-date and accessible was difficult.

Tapping into the data queries built using its legacy software, CPD created a new application using ArcSDE for database maintenance and ArcIMS to serve data to the Web. "As it was, the system was entirely client/server based," says Kezon. "Individual map files were stored locally on roughly 400 personal computers. Anytime there was an update to a map layer or a coding change, we had to manually go out and update all of those personal computers." Using ArcIMS, officers are able to view and edit live data; changes are made to the base data set and are reflected in subsequent viewings.

Esri's GIS tools also tie spatial information to related tabular data, mapping both. For example, an individual police officer can search for all arrestees for aggravated batteries with a firearm within a given geographic area. With CPD's legacy system, such a query would result in a table containing names and addresses as well as individual record information, such as a mug shot or case report number, that the officer would then sift through—the ability to tie tabular data to the area in question was missing.

Mug shot accessibility is a key example of the benefits of marrying tabular and spatial data. "With the ArcIMS system," says Kezon, "we are actually going out live to our mug shot database and popping up the pictures as you hover over the dots on the map. In the old system, you could not see the correlation between the mug shot and the address." The ability to easily pull and view mug shots in the context of a geographic area is groundbreaking.

For more information, contact Joseph Kezon, GIS manager, Information Services Division, Chicago Police Department (e-mail: joseph.kezon@chicagopolice.org, tel.: 312-745-5044).