Tuesday, March 19, 2013

Crime Mapping and the Training Needs of Law Enforcement

Ratcliffe's article Crime Mapping and the Training Needs of Law Enforcement identifies three main aspects of crime mapping, or applications of geographic information systems (GIS): hotspot mapping, CompStat and geographic profiling. Techniques in exploratory spatial data analysis (ESDA) can reveal crime patterns and hotspots of criminal activity that are invaluable to law enforcement agencies. Spatio-temporal mapping and geographic profiling using the GIS methodology is an evolving technique with increasing complexity and can offer vital information for intelligence-led policing in crime reduction and prevention. Ratcliffe mentions that although this technique offers a new form of useful intelligence for law enforcement, it does not undermine non-spatial features of crime records such as modus operandi and temporal variables.

The author defines crime mapping as a way to collect, store, analyze and disseminate information relating to the earth. The first application of GIS in law enforcement is hotspot mapping. This is the input and conversion of crime data into spatial features. The following two images are examples of hotspot mapping of vehicle crimes in Philadelphia for July 2002. In the following two images, Image 1 demonstrates how hotspot mapping appears when each individual crime is represented as a dot while Image 2 shows the same image after using kernel density smoothing. Image 2 is less precise but more clearly displays the actual hotspots.

Image 1:

Image 2:

Although GIS is most frequently used to map property and violent crime, it can also geographically represent calls for service, race and other socio-economic data for a more complex analytical map. It is also effective at demonstrating measurable long-term crime prevention and reduction.

The second application of GIS is CompStat, or Computer Statistics. This is a management process that increases accountability and requires commanders to actively analyze crime patterns. As the author states, it requires a quick conversion of crime data to geographic visuals of the data. The third and final application is geographic profiling, an investigative technique that aids in serial crimes and helps to identify potential criminals on a map. The idea was developed from a combination of theories, including the routine activity theory and rational choice theory that suggest that people develop a daily routine and through knowledge of such a routine, police can identify key nodes for offenders in certain locations. This is helpful in suspect prioritization and patrol saturation.

Ratcliffe claims that while GIS is evolving rapidly and is a crucial element to law enforcement intelligence, agencies are not devoting enough time to training their officers and analysts. He believes that while the number of agencies using it is increasing, many still do not understand its importance and application to policing and are sticking to the traditional policing techniques that they are familiar with.

Ratcliffe's article effectively demonstrates the important of geographic information systems application in law enforcement. The identification and explanation of three aspects of crime mapping was beneficial and their usefulness in the field was evident. He explicitly mentions that geographic profiling produces a map of risk which demonstrates visually the likelihood of criminal activity, the main purpose of intelligence analysis. Through crime mapping, risk can be reduced for a decision-maker.

The author states many limitations to GIS, however. Hotspot mapping has issues with points that overlap, human inability to define clusters and the difficult of establishing broad trends. Some of these concerns are reduced through additional extensions of GIS programs, but the issue of data overload is nevertheless cumbersome. Additionally, geographic profiling is believed to have limitations for some offender types which may have negative implications for risk reduction. Among these were implicit limitations as well, including GIS's ever-evolving nature which makes it difficult for analysts to continuously learn the updates and for new practitioners to enter the field.

While Ratcliffe's article was useful, he redirected to many outside sources rather than including the information within the actual article which made it seem somewhat incomplete. Elaborating further on the three applications of GIS, offering potential solutions to issues in training and explaining the limitations further would have solidified his argument.

Ratcliffe, J. H. (2004). Crime mapping and the training needs of law enforcement. European Journal on Criminal Policy and Research, 10(1), 65-83. Retrieved from http://citeseerx.ist.psu.edu/viewdoc/download?doi=


  1. Ratcliffe's article thoroughly explains the three components to crime mapping and its benefits to law enforcement agencies. Evidently, crime mapping has its advantages and disadvantages. Although GIS is able to map calls for service, this is unlikely to be beneficial for law enforcement agencies. The goal of crime mapping is to determine crime trends, patterns, and series. Some law enforcement agencies receive a large volume of calls for service and not all of them are related to crimes. Also, the place where the service call came from may not be the location where the crime occurred. In addition, if one were to map a large volume of calls for service, the map will be difficult to interpret. Hence, analysts may not be able to determine clear trends and patterns of crime.

    1. That is an interesting point, Nuwanti, I did not consider all of those disadvantages of mapping calls for service.

  2. It is interesting that Ratcliffe discussed geographic profiling in terms of it being part of the larger method of crime mapping. I see the two as related but distinctly different methods. Crime mapping in terms of hotspot mapping and CompStat can be highly useful for most law enforcement agencies if applied properly and with correct training. Geographic profiling on the other hand requires specific crime trends for it to be applicable, many of which smaller agencies will rarely if ever encounter. Additionally, the utility, application, and purpose vary greatly between hotspot mapping and geographic profiling, despite their shared root in GIS.

  3. I think that hotspot mapping is a very valuable tool for law enforcement and law enforcement analysts. From comparing the two images I agree with Ratcliff's position that humans have a hard time identifying clusters. The second image makes the hotspots much more apparent to me, even though they are showing basically the same data but in a different way. I also think that hotspot mapping could be invaluable for a business that wants to open a new store, but wants to make sure it's in a relatively safe area. Analyzing where crime is predominantly located and utilizing past trends to forecast expected safer areas to open a shop would work well for these businesses.