City of Lincoln
Police Department
ACUDAT
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City of Lincoln Police Department ACUDAT |
ACUDAT is the Lincoln (Nebraska) Police Department's geographic crime analysis process. The acronym stands for Analyzing Crime Using Data About Trends. This phrase was coined in the spring of 1998, as LPD began holding regular meetings to review data from its geographic information system (GIS) and its computerized police records. The key components of the ACUDAT process are:
While an increasing number of law enforcement agencies are implementing crime mapping applications and meetings styled after New York City's COMPSTAT, Lincoln has several years' experience in this field, and our process has a few elements that may be especially noteworthy and have added particular value to our GIS efforts. Some of these distinguishing features of ACUDAT follow.
An enterprise GIS
The City of Lincoln and Lancaster County began developing a geographic information system in 1990. Led by the engineering disciplines (County Engineer, City Public Works Department, City/County Planning Department), a cohesive GIS emerged, with many City and County agencies sharing GIS products. By the mid 1990s, the City's Intergraph system and the County's ArcInfo system were totally merged into an ArcInfo GIS. During the second half of the 1990s, many other City and County agencies began using ESRI's desktop GIS, ArcView. Today, agencies such as the County Assessor, City/County Health Department, Lincoln Police Department, Lincoln Public Schools, Lincoln Electric System, Lincoln Parks and Recreation Department, and many others make extensive use of ArcInfo and ArcView. The police department's involvement in GIS began in the fall of 1997.
The City/County GIS resources are largely shared, and common files reside on a networked server for access. As a result, all agencies use shapefiles and coverages created and maintained by other agencies to the largest extent possible. This is particularly valuable for large and complex files, such as the centerline streets file. For example, the Lancaster County Assessor maintains a polygon coverage consisting of over 90,000 land parcels, connected to the assessor's Oracle database of property records. Many other agencies use this for their own GIS purposes. Coverages of streets, parcels, waterways, parks, schools, political boundaries, utilities, geographic features, and other GIS elements are regularly updated and maintained by their host agency, but constantly available for use by all City and County agencies. The City/County GIS enterprise includes a regularly updated set of orthophotos for the entire County, at one meter resolution in rural areas, and one foot resolution in urban areas.
A GIS user's committee for City and County employees meets monthly, and is coordinated by the Planning Department. Employees from many agencies participate in seminars, demonstrations, and share tips and information about ArcView, ArcInfo, and other elements of the GIS. The enterprise uses central purchasing, information services, and training. Several high-end plotters and printers are networked for shared use by multiple agencies.
An automated geocoding process
The Lincoln Police Department has benefited tremendously from an extensive and highly customized computer records management system implemented in 1979-80, and continuously updated and refined. In 1997, the department's Information Technology Unit created automated routines to clean and export data from the department's records management system for geocoding within ArcView. These data are exported as comma-delimited text files, a format easily imported by ArcView. For three years, staff queried the records database, exported the results to files, imported these as ArcView tables, and geocoded the tables. Although quite effective, the process has been streamlined and automated more recently. The department obtained services and software from the Omega Group (CrimeView) to automate the geocoding of these downloads and append the results to ArcView shapefiles. The Omega Group's scripts written in ArcView's Avenue programming language were customized to meet the department's specific data format and needs. Now, each day at 0500 hours, delimited text files of dispatch records, incident reports, gang contacts, registered sex offenders, parolees, and field interviews are automatically downloaded and geocoded. Dispatch records and incdent reports are appended to existing master shapefiles, while gang, field interview, parolee, and sex offender shapefiles are overwritten with updated versions (since these data often change from day to day.) This near-real-time data is then available for all authorized users in their existing or new ArcView projects. GlobalSCAPE CuteFTP software is used to schedule queues that further automate the transfer of updated shapefiles to client computers. In addition, refreshed shapefiles are sent via FTP to the City's web server, to maintain an interactive ArcIMS project on the police department's Internet site.
A decentralized and mobile GIS environment
Unlike many agencies, GIS at the Lincoln Police Department is dispersed to multiple users in various units. Although the department's Crime Analysis Unit is the primary GIS user, Several users access GIS data with notebook computers, retaining basic geographic map features on their hard drives, and downloading new shapefiles of incidents and persons on a daily basis. Employees use either ArcView or ArcExplorer as a client application. Two fully-enabled GIS workstations are available to all officers and employees. Limited functionality is also provided by the department's Internet mapping application, requiring no client software. The department has deployed a simplified GIS project to mobile data computers on a limited trial basis, and is presently exploring a more robust Intranet mapping application.
This decentralized configuration is a reflection of the department's attitude towards geographic crime analysis and crime mapping. The department believes that the primary value of this process it to provide timely information to field personnel that helps them plan their work and empowers their investigative and preventative efforts. In furthering this philosophy, the department makes use of several customized projects and extensions to make GIS more approachable to staff with limited GIS experience. The most obvious example is the use of the CrimeView extension, which significantly simplifies queries and reports that are rather complex with ArcView alone.
Field-focused meetings
LPD's monthly ACUDAT meeting is designed to share information among field personnel-sergeants, officers, detectives, and investigators. While many commanding officers may attend, the meetings are clearly focused on getting valuable information to the street. Led by the police chief (who is the department's most experienced GIS technician), department members who attend this wholly voluntary evening meeting examine crime trends for auto theft, burglary, indecent exposure, larceny from auto, and robbery. This examination begins with an ArcView project with these crimes as individual shapefiles. Any apparent clusters are reviewed by examining the theme table fields of the individual incident, or looking at the actual on-line police reports in the department's records management system. An LCD projector is used to project the ArcView project and the records terminal emulator onto a screen. An important additional component of ACUDAT is the exchange of suspect, offender, and intelligence information.
A typical ACUDAT meeting will include briefings by a knowledgeable officer on a serial or repeat offender, a recent arrestee, a crime series with an unusual MO. At all ACUDAT meetings, clear crime patterns, previously unknown, will be identified. In some cases, single cleared offenses are identified that appear related to other similar offenses nearby. Assignments for further follow-up often result from these revelations. It is common to access and project other data, such as mugshots from the department's digital imaging system, or photos of residences from the County Assessor's web site during the discussion of a particular person or place. ACUDAT meetings commonly result in both specific investigative leads, and in broader strategy initiatives. Several crime prevention initiatives have been spawned at ACUDAT.
Although GIS is an important element of ACUDAT meetings, the exchange of information and ideas is its primary value. In many instances the ArcView project is merely the catalyst that begins this discussion and exchange. A particular challenge with ACUDAT has been to keep the meetings within two hours. The meetings are held at night to maximize the opportunity for late shift personnel to attend. ACUDAT meetings have served to acquaint an increasing number of personnel with the department's GIS, records management, digital imaging, and Internet resources, as well as the informational resources available from other agencies, and to stimulate more frequent daily use of ACUDAT resources.
Public access to GIS information
LPD is one of a handful of police agencies that makes available interactive near-realtime crime mapping applications on the Internet. The department uses both ArcIMS and MapObjects applications. The most recent addition, CrimeView Community from the Omega Group, offers extensive query capability. The department deployed its first interactive web mapping application in April, 1999. In this MapObjects application, selected offenses including murder, robbery, assault, burglary, narcotics offenses, vandalism, and larceny from automobile are available with limited query capability. This data is available city wide for the current calendar year. Separate projects for the preceding two calendar years are also on-line. To protect the confidentiality of victims, all data fields except case number and date are redacted from the data Mapping applications are accompanied by links to more detailed information about interpreting maps and understanding geocoding.
In addition to the interactive application, the department makes available more complete and extensive tables of significant police incidents at the neighborhood level. This application allows citizens to navigate to their own immediate neighborhood, then access a table of incidents within the past 60 days. Addresses are padded out to the block number, certain offenses are redacted to protect victims (sexual assault, child abuse, missing persons), and some offenses (shoplifting and check offenses) are redacted to avoid slowing download times. Although both of these applications require either good patience or fast connections, they are quite well used. Together, these applications are generating 50,000 to 60,000 hits monthly on the police department's website. All of these applications employ scripts and routines that automate their daily update, requiring only occasional and minimal attention from staff.
The public also receives limited GIS crime trend information in printed form. Lincoln's daily newspaper, the Lincoln Journal Star, began publishing crime maps in 1999. The Journal Star presently publishes three maps weekly, Thursday through Saturday. These are simple layouts that display the past weeks' vandalism, auto theft and larceny from auto, and burglary. The paper is presently working on methods for publishing tabular information about these crimes along with the maps. LPD produces these layouts on Wednesday mornings for the Journal Star. Text files are exported in .csv format, and layouts as encapsulated PostScript files. These files are then emailed to the newspaper's graphic arts department. The entire process is completed in about 15 minutes.
The City/County Information Services Division controls and maintains a growing number of on-line interactive mapping applications on the City/County web site, including applications from the Police Department, Parks and Recreation Department, Planning Department, and County Assessor's Office. The Assessor's application, in particular, is an outstanding example of the capabilities. A parcel level map is linked to the detailed records in the Assessor's Oracle database, which is in turn linked to a digital image of the premises, and to digital images of instruments held by the Register of Deeds.
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