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GIS in Forensic Investigations
Cyndi Comfort
Annotated Bibliography
GEO 565 – Winter 2009
GIS and Related Technologies Used in Criminal and Environmental Forensic Investigations
The following annotated bibliography is a compilation of journal and academic articles on how GIS and related technologies can be used to enhance the work of criminal and environmental forensics. There are various applications reviewed that law enforcement and federal agencies can utilize these technologies for, to assist in their investigations. Using maps to display areas of damage or criminal activity has been used for years. GIS enhances these mapping capabilities by allowing for feature overlay and subsequent analysis of related data. GIS is dynamic and interactive, and new and innovative applications are always emerging. The ability to visually assess geographic areas and analyze their relation to criminal and environmental activities is only limited by accurate data and the ability to access that data.
Articles:
Levine, N. (2006). Crime Mapping and the Crimestat Program. Geographical Analysis 38(1), 41-56.
Crimestat is a spatial statistics tool that was funded by the National Institute of Justice, and created by the author of this article to interface with most desktop GIS programs. Crime mapping is used to map crime incidents and detect patterns so police can focus their prevention and enforcement effort in those areas. Crimestat also attempts to help law enforcement personnel identify and apprehend offenders and prevent future crimes. The statistical functions in the program include spatial description, spatial autocorrelation, hot-spot analysis, spatial modeling, journey to crime analysis (a.k.a. geographic profiling), space time analysis, and crime travel demand. These different analyses in the Crimestat/GIS interface allow police departments nationwide to simulate, predict, and visually monitor crime and incidents better than ever. Future versions of the Crimestat program will expand the program to incorporate the needs that users in law enforcement have articulated.
Grip, R.W., Grip W.M., & Morrison, R.D. (2000). Application of Aerial Photography and Photogrammetry in Environmental Forensic Investigations. Journal of Environmental Forensics, 1, 121-129.
This article explores the critical aspect of acquiring aerial photographs for a forensic analysis of environmental damage. These photos can be acquired privately or publically. Private libraries cost more money, but are faster on request turn around time. The United States Geologic Survey (USGS) has a summary of all public photos, where the Management Association for Private Photogrammetric Surveyors (MAPPS) is a national association of private sector firms. Multiple types of photographs, such as stereoscopic, infrared, color, and black and white are available for a variety of uses. There are standard identifiers on each photograph that tell when the photo was taken, the scale of the photo, the altimeter of the plane, and focal length that can help when comparing to other photos. Stereoplotters allow photos to be digitally scanned without creating distortion. GIS can analyze and corroborate information with these aerial photos to help establish presence and timeline of environmental crimes.
Adpinar, E. & Usul, N. (2004). Geographic Information Systems Technologies in Crime Analysis and Mapping. 2004 ESRI User Conference. 1-12.
This article analyzes the use of GIS in mapping and analyses of crime in Cankaya district, and the relationship between land use and incident location. The data studied included spatial and temporal patterns of incidents, the relationship between incidents and land use, and the socioeconomic data associated with the incidents. Interpolation of existing data helped to establish “hot spots”. This study also looked at the rate of incidents based on land use. GIS was used extensively to calculate the proximity of crime incidents to land use and generate areas where future zones with a heavy police presence should be. The ability of GIS to organize, manage and analyze data makes it a powerful tool that helps understand past crime, prevent future incidents of crime, and respond effectively.
Agosto, E., Ajmar, A., Boccardo, P., Giulio Tonolo, F., & Lingua, A. (2008). Crime Scene Reconstruction Using a Fully Geomatic Approach. Sensors, 8, 6280-6302.
This paper attempts to describe the process for an accurate and geomatic reconstruction of a suspect’s foot path through a crime scene by analyzing the bloodstains on the ground. Crime scene photos taken by first aiders are crucial to the accurate reconstruction, as they are taken before anything is moved and the crime scene is virtually untouched. For this reconstruction, it is also important to have the suspect’s shoes available for proper identification. Laser scanners and close range photogrammetry are two tools that allow for accurate referencing of points, 3D reconstruction, and mapping of the scene for courtroom use. Photographic rectification is also used in cases of reconstruction to help eliminate distortion from non-metric photos. These rectified images can be georeferenced in a GIS layer. Once a simulation of a foot walk with the suspect’s shoes is done, a statistical evaluation can be done on the chances of walking through a blood stained scene and not coming into contact with the blood on the floor. GIS analyses like this can be crucial procedures for simulation and modeling in a courtroom.
Chen, X., Elmes, G., Lin, G., & Walnoha, M. (2008). Developing a Spatial-Temporal Method for the Geographic Investigation of Shoeprint Evidence. Journal of Forensic Sciences, 54(1), 152-158.
Shoeprint evidence collected at crime scenes can be downloaded into a database and analyzed by GIS spatially and temporally. The common functions of GIS in law enforcement are detecting crime patterns, analyzing hot spots, and mapping crime scenes. Utilization of shoeprints as evidence is often underutilized or overlooked. There are four ways in which mapping of the crime can help forensic shoeprint analysis. Mapping can distinguish clusters at many different scales. Crimes can also be mapped on a time line. Thirdly, crimes can be grouped by frequency of location and type of crime. Finally, shoeprint retrievals can be enhanced and stored in a GIS data base and linked to other crime scene data. Because many criminals are repeat offenders, shoeprint data can enhance other forensic data by linking repeat offender with matching shoeprints and modes of operation, that happen in geographically and temporally connected crimes. Shoeprint treads must be highly identifiable by make, model, size and wear for matching to other prints. The probability of similar shoeprints being from the same suspects decrease with time and distance. GIS can help with algorithms to eliminate improbable suspects down to a manageable number for further investigation.
Brilis, G.M., Gerlach, C.L., & van Waasbergen, R.J. (2000). Remote Sensing Tools Assist in Environmental Forensics. Part I: Traditional Methods. Journal of Environmental Forensics, 1, 63-67.
This first paper in a two paper series is a study of the use of photogrammetry, topographic mapping and aerial photography in identifying, analyzing, and managing environmental damage. The original version of Remote Sensing was aerial photographs taken from hot air balloons, which provided an unbiased view at a specific time. In modern times photos taken from satellites or airplanes may be used to quantify information for photogrammetry. Data inputted in to the digital photogrammetric system can be rapidly produced, reproduced, have the distortion corrected, and be transmitted to the GIS for analysis and display. Aerial photos can also be used for cartographic information and digitized to create thematic maps or overlays. Measurements from these photos can be made to plot changes and referenced in a coordinate system. These photos are powerful tools for establishing a permanent record of past and present environmental conditions. Topographic or elevation maps can also be created form aerial photos and entered into a GIS system for referencing and analysis. They provide a quantitative way to understand the spatial relationships and locations of real world features such as hazardous waste sites. These maps can be used for comparisons to past records and to exhibit changes over time.
Brilis, G.M., Gerlach, C.L., Stokely, P.M., & van Waasbergen, R.J. (2001). Remote Sensing Tools Assist in Environmental Forensics: Part II – Digital Tools. Environmental Forensics 2, 223-229.
The second paper in the series provides an assessment of how the application of Remote Sensing tools described in Part I can be integrated with GPS and GIS for rapid collection and analysis of geospatial data. The EPA sponsored both of the articles and they are just one of the federal agencies that utilize GIS technology for its investigations. There seems to be an emerging trend of combining GIS with internet applications for better database management. The ability of GIS to integrate specialized data in a visual geographic analysis provides an effective means of clearly displaying information otherwise hard to interpret. Analysis capabilities that are utilized frequently include: Measurement of specific features, attribute reclassification, topological overlay, connectivity routes, the ability to transform coordinates to common systems, and surface analysis. GIS’s ability to overlay features for comparison and analysis has successfully been utilized for many EPA investigations. Project planning for GIS can be broken down to six vital areas: Defining project objectives, defining analytical requirements, making the data available, development issues associated with the data, metadata and implementation. Relational database management is vital to the ability to query, manipulate and extract geographic attribute data in a GIS. Remote Sensing data and the capabilities of GIS are mutually beneficial. GPS receivers can receive varying levels of point reading accuracy. These points can be integrated with a GIS for the recording of values and overlaying the data on aerial photos. These points can then be georeferenced visually and appropriate attribute data can be extracted.
Johnson, C.P. (2000). Crime Mapping and Analysis Using GIS. Conference on Geomatics in Electronic Governance, retrieved from website: http://www.cdac.in/html/pdf/geom4.pdf.
This article reviews the many applications of GIS that can make it a significantly beneficial tool for law enforcement and emergency response personnel. GIS is already widely used by many agencies for crime analysis, criminal tracking, traffic monitoring, mapping, and various other spatial applications. The internet provides many possibilities for sharing and sending mapping data for interagency use. Crime mapping can integrate community characteristics, display spatial patterns of events, and produce thematic maps to support data. GIS can help analyze crime data tactically, strategically, and administratively. Radial analysis can be performed, hotspots can be identified and compared over time and type, and many other variables displayed and integrated to help with the investigation. GIS can also help investigate serial offences, predict behavior from past crime history, and identify subjects with geographic profiling.
Ratcliffe, J.H. (2004). Geocoding crime and a first estimate of a minimum acceptable hit rate. Geographical Information Science, 18(1), 61-72.
This article reviews the use of geocoding in crime analysis and the minimum acceptable hit rate that should be allowed. Geocoding is the process of converting locations into grid coordinates. This is a regular task for crime analysts. Some locations can be difficult to map for various reasons, and errors in the geocoding process can translate into compounded errors in the analysis and assimilation of data. GIS is at the forefront of intelligence led policing. Data capture and geocoding data elements are the two most important components of the crime mapping process. Given data quality issues that are inherent in crime databases, this paper investigates accuracy problems of geocoded points and the minimum acceptable geocoded hit rate. After much configuring the author suggests 85% as a minimum rate, pointing out that is still a high error margin. Continuous efforts to reduce errors need to be implemented to improve geocoding efficiency.
Leitner, M., Listi, G.A., & Manhein, M.H. (2006). The Application of Geographic Information Systems and Spatial Analysis to Assess Dumped and Subsequently Scattered Human Remains. American Academy of Forensic Sciences 51(3), 469-474.
This article studies the application of GIS and spatial analysis on the recovery of dumped and scattered human remains in southern Louisiana. The goal was to determine if there was a selective bias for the dumping of human remains. Factors considered were location of dump site, season the remains were dumped, and proximity of dump site to nearest road or waterway. Coordinates for all elements of the found skeletal remains were entered into ArcView GIS for further analysis and mapping. Dispersal patterns were assessed using Crimestat III, a spatial statistics program. The variables considered were dispersal distance, direction, and post mortem interval. Results of both analyses found approximately three quarters of the remains dumped were in rural areas. Among these rural cases 89% were dumped away from a building structure, and 49% were dumped in a wooded environment. Conversely, the urban cases showed a majority of dumped remains in open areas and almost half were in direct view of a building structure. In both areas the longer it took to locate remains, the farther the skeletal elements were from the original dump site. A large portion of dump sites were within a quarter mile of a road. The authors concluded that if the remains were not recovered in the first twelve hours after being reported missing, that it is likely they have been dumped in a rural area, within one quarter mile of a road, and more likely to be found in a wooded area.
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