Crime Mapping & Analysis

William Jarvis & Ibrahim SabekCSCI 5715

Prof. Shashi Shekhar

Wilson, Ronald and Filbert, Katie. “Crime Mapping and Analysis.”

Encyclopedia of GIS. Ed. Shashi Shekhar & Hui Xiong. New York: Springer Science+Business Media, 2008.

Definition

●Intersection of three sciences: Geography, Sociology, and Criminology.

●A bunch of techniques●Visualizing raw geographic data.●Analysing geographic features for patterns.●Uncovering spatial interactions between features.

Background●1930 - 1970 → Social Disorganization ●Chicago School of Sociology.

●1970 - 1990 → Environmental Criminology ●Social Disorganization + GIS software.

●1990 - present.●Funding crime mapping research centers.

● Tobler’s First Law of Geography.●Places are not isolated islands of activity.

●Interactions, such as social, demographic, or economic occur within and between places ●The closer you are in space, the more related you are

●The basic foundation for the concept of distance decay

Scientific Fundamentals

Applications● Five key applications:● Thematic Mapping

● Non-Graphical Indicators

● Hot Spots

● Spatial Regression

● Geographic Profiling

Hot Spots● Hot spots (and their inverse, cold spots) are places with a

greater (lower) than average level of crime.

● Done by many agencies to provide guidance in resource allocation

● Analysis can occur at a variety of scales, macro to micro● E.g. high crime neighborhoods vs. high crime centered

around a particular bar

● Level of analysis allows police to take specific actions from more patrols to investigating and serving warrants (Champions Bar & Grill in Minneapolis)

Graffiti Hot/Cold Spots in Lincoln, NE

Source: “Extended Crime Analysis with ArcGIS Spatial Statistics Tools.” Accessed at http://www.esri.com/news/arcuser/0405/ss_crimestats1of2.html. Last accessed 10/7/14.

●Question: Given a data set, can hot/cold spots be found via SQL/OGIS query?

●No, must be calculated be calculated via spatial statistics.●Nearest Neighbor Index

●Crime incidents geocoded on map, distance between incident and neighbors calculated●Distances summed then divided by number of incidents in area of analysis●Next, map of random incidents is made, and the same calculation repeated on these random incidents.●Ratio of two numbers = NNI. NNI < 1 means data are clustered.

●STAC (Spatial and temporal analysis of crime ellipses)●Create circles of decreasing radius around each crime incident●Areas of greatest overlap indicate hotspotsImage source: http://en.wikipedia.org/wiki/Crime_hotspots. Last accessed 10/8/14.

Geographic Profiling● Technique for identifying likely anchor point of a serial

offender (for example, residence).

●Utilizes crime place and routine activities theory, with the assumption that criminals don’t go far out of their daily routines to commit crimes

● Takes into account a series of crime locations associated with a particular serial criminal and creates a probability surface to identify the offender’s anchor point

Future Developments●Work done in three areas●Research and Technology Centers●Primary resources for research, development, and

application of GIS, spatial data analysis methodologies, and geographic technologies

●Software Development●CrimeStat●GeoDa

● Law Enforcement/Criminal Justice Agencies primarily focus on utilizing data to more efficiently prevent/fight crime

Relation to CSCI 5717● Will be exposed to this topic in Chapter 7.● Applications of spatial data● Spatial data mining to discover trends

Questions?