Utilization of Officer Locations for Strategic Crime Analysis

By Daniel Polans

The Milwaukee Police Department serves approximately 600,000 people and is the largest police agency in the State of Wisconsin with about 1,900 sworn personnel. Milwaukee is approximately 90 miles north of Chicago, Illinois and is located on the shore of Lake Michigan. The city is home to professional sports teams, including the Milwaukee Brewers Major League Baseball team and Milwaukee Bucks National Basketball Association team. The city contains multiple visitor attractions, including the Milwaukee Art Museum, Harley Davidson Museum, Miller Brewery, Summerfest Musical Festival and more. The University of Wisconsin- Milwaukee has its own police force, but works in partnership with the Milwaukee Police Department to protect and serve the campus and students.

The Milwaukee Police Department’s Vision Statement is: “A Milwaukee where all can live safely and without fear, protected by a police department with the highest ethical and professional standards”. The Milwaukee Police Department’s Mission Statement is: “In partnership with the community, we will create and maintain neighborhoods capable of sustaining civic life. We commit to reducing the levels of crime, fear, and disorder through community-based, problem-oriented, and data-driven policing.”

Crime Analysts in the Milwaukee Police Department are assigned to the Intelligence Fusion Center (IFC), which is responsible for tactical analysis. Crime Analysts are also assigned to the Office of Management, Analysis and Planning (OMAP), which is responsible for administrative analyses. Strategic crime analysis is performed at both work locations. The following article is an innovative, practical and strategic example of data-driven crime mapping supporting the mission of the Milwaukee Police Department.

A team consisting of a Sergeant and a Crime Analyst from the Milwaukee Police Department enabled a GPS tracking system on a smart phone to capture officer locations. The location was captured from the officer’s smart phone in the form of GPS coordinates. The officer location data was then spatially and temporally compared with Calls for Service (CFS) data. The study demonstrated how officer location can be compared with CFS data for strategic planning and effective deployment of police personnel.

The Police Sergeant installed an open source GPS tracker application (Traccar) – listed for free in the Android marketplace – on his cell phone. The GPS tracker was enabled for approximately three hours from 9 p.m. to midnight while driving through the north side of the city of Milwaukee. GPS coordinates were collected approximately every 2-3 minutes during the three-hour period. Latitude and longitude coordinates and times were stored in an electronic database and exported as an Excel spreadsheet. The analyst then utilized ArcGIS mapping software from Esri to map the coordinate data, police district boundaries, and calls for service from the Milwaukee Police Department’s Computer Aided Dispatch System (CAD).

The GPS coordinates of the Sergeant (black squares) and the calls for service (red dots) were mapped (Figure 1). Military time (a 24-hour clock) was recorded for each location. The priority of the call (P1-P4) is also listed. P1 calls are the most serious. Data was joined with calls for service, which provided time and distance data from the closest GPS coordinate. GPS coordinates for 148 instances were recorded from the tracking application and 77 calls for service were placed by citizens. Fifteen of the 77 calls for service (19 percent) were placed on the north side of Milwaukee and were sampled for the study.

Figure 1: Police Sergeant GPS activity and calls for service mapping

Figure 1: Police Sergeant GPS activity and calls for service mapping

The 15 calls for service were each compared with the closest GPS coordinate (Figure 2). The average distance between those calls for service and the closest GPS coordinates was 4,314 feet (less than 1 mile). Collecting GPS coordinates allows crime analysts to quantify if officers are in correct locations at accurate times. This can be achieved by measuring the difference in distance and time from officers’ positions relative to calls for service. For example, call number 6 was the call for service where the Sergeant was the closest in both distance (77 feet) and time (2 minutes).

Figure 2: District 4 calls for service compared to closest GPS coordinate (distance and time).

Figure 2: District 4 calls for service compared to closest GPS coordinate (distance and time).

The majority of calls for service between 9 p.m. and midnight occurred in the south end of the District. However, the Sergeant’s route included the northwest side of the District where no calls for service occurred. Utilizing GPS coordinates from police officers can support strategic crime analysis by evaluating officer’s GPS locations in comparison to calls for service and crime incidents to help place resources in the right locations at the right times, which is a fundamental responsibility of the Crime Analysts.

Crime Analysts should consider utilizing GPS data for strategic deployment. This study showed that it is relatively easy and inexpensive to collect officer location data utilizing open source software. As part of their daily responsibilities, Crime Analysts usually have access to other data required for analysis, including data from Computer Aided Dispatch (CAD) system, crime data, and mapping software.

Tracking GPS coordinates through this method provides a new dataset and expands upon currently available data, including calls for service, incident reports, and proactive activity measures which can aid in tactical and strategic decision making. Current GPS on squad cars limits officer location data to vehicles, whereas GPS tracking on phones can record coordinates from officers on foot, riding bicycles, as well as while driving. Further, the GPS data collected from vehicles may not be readily available to crime analysts for reasons such as volume of data and security clearance.

Officers, especially those with supervisory responsibilities, can volunteer to install the GPS application on their phone and have control of when the GPS is tracking their locations. Even periodic use could improve efficiency when it comes to resource management. Some officers may reject the idea of GPS tracking, but many officers interested in improved technology may volunteer. Officers will be interested in receiving maps of their coordinates, calls for service, and crime incident data with symbols based on crime type. Analysts collecting the data should be willing to supply and discuss their map products with the officers who provide the coordinates and be willing to make adjustments to meet their needs.

Many open source GPS tracking applications exist and individuals interested in this type of analysis should research applications and determine which are safe to use in their work environments. Crime Analysts and IT personnel could collaborate and assist in this assessment. Multiple security concerns exist on the collection of real-time and location data for police officers. This data must be stored in a secured server and meet specific security standards to prevent misuse. The frequency of recording coordinates can be set by each officer (30 seconds, 2 minutes, etc.) to increase privacy of officers and the battery life of their phones.

Further analysis should include an entire shift (at least 8 hours) for a single sergeant. Multiple sergeants can then team up to cover major crime affected areas. A follow-up could include collecting coordinates from multiple officers of different ranks and provide a database so that supervisors can allocate officers to high crime or high calls for service locations. Analysts could use a large dataset of coordinates to create a density map that compares hotspots of calls for service or crime to officer routes throughout the jurisdiction. Collecting and mapping coordinates from officers assigned to an initiative with specific boundaries could determine if police personnel were on the right streets at the right time when crimes and calls for service occurred. A larger sample of officers is needed in order to generalize results for useful mapping purposes. Crime Analysts and other practitioners are needed to use the GPS coordinate data to improve strategic crime analysis.

Daniel Polans

Daniel Polans graduated from the University of Wisconsin-Milwaukee, majoring in Criminal Justice, and is a Crime Analyst with the Milwaukee Police Department. He received the First Place Award for Crime Mapping with the Milwaukee Police Department Crime Analysis Unit from the International Association of Crime Analysts in 2013. He also was a scholarship recipient from the International Association of Crime Analysts in 2013.

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