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Spring 2004
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In the Province of Buenos Aires, Argentina, GIS Aids Crime Mapping

  click to enlarge
BAPPD had transformed more than 1,000,000 street records and was able to complete the basic modifications to the Crime Recording System to make it GIS friendly.

The population of Argentina is roughly 36 million, with the Province of Buenos Aires containing approximately 40 percent of the country's total population (almost 14 million inhabitants in 307,571 square kilometers). Surrounding Buenos Aires, the population density can be as high as 10,000 people per square kilometer whereas areas further out in the province can have less than one person per square kilometer.

The Conurbano is the name given to the Buenos Aires metropolitan area. This area includes approximately 30 counties, with 9.5 million inhabitants within a mere 5,600 square kilometers. To the Buenos Aires Province Police Department (BAPPD), which comprises more than 45,000 officers scattered in more than 130 counties within the province, the Conurbano is the most important zone with regard to crime levels.

The goal of BAPPD was to develop a crime mapping and analysis capability. BAPPD began by developing a computerized system of locating crimes on digital maps to provide its police force with information regarding the distribution of crimes within its area of responsibility. The system later became more sophisticated by being capable of performing specialized spatial analysis and hot spot detection.

The Beginnings of Crime Mapping

In 1998, BAPPD obtained basemaps for the Conurbano area and some other significant urban zones, which were used to develop the system. Later, BAPPD expanded to cover the whole province. Also, based on the recommendations of the government agency that provided those basemaps, BAPPD ventured into GIS using ArcView, provided by Aeroterra S.A., Esri's distributor of products in Argentina. As time went by, BAPPD gathered a group of talented professionals into a task force that developed a set of methodologies and procedures for producing state-of-the-art spatial analysis using innovative techniques and software products and, thus, provided a better service to the community.

As the BAPPD task force began, one of its first functions was to identify how to efficiently map the crime locations. It began by first manually locating each incident and to no surprise found it to be a laborious and time-consuming activity. Because of the particular Argentinean address style, the task force had problems geolocating incidents based on their address locations. Eventually this process was improved when Aeroterra developed code to work with the ArcView geocoding engine that added a new style—named the "Argentine Address Style"—to the default addressing templates provided with the basic ArcView installation.

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Surrounding Buenos Aires City, the population density can be as high as 10,000 people per square kilometer whereas areas further out within the province can have less than one person per square kilometer.

Once BAPPD overcame the addressing challenge, it came up against a second challenge. Although the task force now had a working addressing style, the department's street basemaps were not designed for use with the new style, nor was the crime database. Then began the transformation of street centerlines for more than 30 cities to make them compatible with the required fields of the Argentine Address Style. Following came the conversion of information about crime locations in the central crime database. Other challenges included developing a data dictionary, designing a proper way to write addresses and store them in the crime database to be readily usable by the GIS, error checks, and safeguarding procedures.

Within a short time, BAPPD had transformed more than 1,000,000 street records and was able to complete the basic modifications to the Crime Recording System to make it GIS friendly.

By 1999, BAPPD was able to start crime mapping. This began by first constructing many pin and choropleth maps, but BAPPD was eager to start some sort of aggregation analysis. It experimented with various additional spatial and crime analysis packages until its task force found CrimeStat software (www.icpsr.umich.edu/nacjd/crimestat.html), which was developed by Ned Levine & Associates, Houston, Texas, under grants from the U.S. National Institute of Justice. This package worked well with GIS software and provided the specific analysis BAPPD was looking for. By 2000, BAPPD was able to begin creating geographic profiles of crimes to provide to its crime analysts.

Creating Decentralized Crime Mapping Units

Until late 2000, the majority of the mapping project was supported by the central crime mapping unit, but the main focus of the project was always to create decentralized structures comprising relatively small areas (two counties at most) and allowing them to share common concepts, methodologies, and more.

  GIS team at BAPPD
The team of crime mapping GIS professionals in BAPPD believed that part of its success in getting so much accomplished was because of strong support especially from the management staff.

During 2001, the Buenos Aires Province Ministry of Security adopted a new policy regarding crime mapping and promoted the creation of decentralized crime mapping units coordinated by a central crime mapping unit. In 2002 BAPPD launched a GIS-based crime analysis campaign, including press coverage, using ArcView 8.x along with cartography and geocoding style licenses provided by Aeroterra.

After almost four years, BAPPD now has detailed 1:5,000-scale maps of the Conurbano area and every urban center in the province with more than 2,000 inhabitants. At this scale BAPPD has been able to develop a geodatabase with basemaps that include street centerlines, city blocks (parcels, etc.), census tracts, hydrographic information, and railroads. It has also enriched this database with locations including schools, hospitals, banks, and parks. Included in this data is the actual crime database, with valuable information about crimes recorded at the incident level as well as information recorded as aggregated counts at specific times and with aerial units.

For more information, contact Gastón Pezzuchi, crime analyst, BAPPD (tel.: 054-221-4231750/1760, ext. 4852; e-mail: gpezzuchi@sidic.pol.gba.gov.ar or gpezzuchi@way.com.ar), or Jorge Hector Ortiz, chief, BAPPD (tel.: 054-221-4231750/1760, ext. 3438; e-mail: jortiz@mseg.gba.gov.ar or jorgeortiz@mseg.gba.gov.ar), or visit Aeroterra at www.aeroterra.com.

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