C7

Chris McCormick

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Many police jurisdictions create crime maps, displaying visually where crime hot spots occur, and by extension, where they don't. These maps are useful in knowing where to improve police patrols and to dedicate sometimes scarce resources.

Crime mapping has been done for some time, and has been credited with solving high-profile serial homicide cases, for example, where it has been difficult to see the connections between individual cases or to trace the movements of the perpetrator.

It can also be coupled with a mathematical program in a process called geographic profiling, and has had success in locating where criminals live based on the patterns of the crimes they commit.

What is new is making these maps available to the public, in the interest in sharing information on community safety and security. Many police jurisdictions now publish these maps. In Ottawa, for example, the police service has merged Geographic Information Systems technology with police calls-for-service data.

Ottawa uses an American company, CrimeReports.com, which takes police crime statistics and geo-locates it on a Google map. The map is produced with markers for various crimes, such as burglary, theft, homicide, breaking and entering, and so on. You can adjust the information to display information in different ways, for example on dates, and area.

The Ottawapolice.ca website says this is a way to further community awareness and to improve accessibility to calls-for-police-service in the community. While the Ottawa Police Service say they caution people against using the maps to make comparisons about the safety or crime levels in an area, it is difficult to imagine people not doing that.

The Toronto Police Service also makes similar qualifications, and will not even let you view the crime maps unless you agree to their definition of what the data does, and does not, represent.

However, the first thing I did in looking at Ottawa's crime map was to try to see where the crime hot- and cold-spots were. I don't know Ottawa very well as a city, but I've been there a few times, and consistent with my impressions, I was in a fairly safe area.

I then looked at a neighbourhood crime map of Toronto, and discovered a robbery two blocks from where I used to live, and a theft of a vehicle three streets away. The robberies seemed clustered along main streets, and there were more homicides downtown than in the university area.

That was a mildly amusing waste of time, but doesn't come close to the experience of walking home at two o'clock in the morning along a dark downtown street.

You can even sign up to get a crime map alert by email, but it's not quite as exciting as listening to the police scanner.

Such police sites usually caution that a data point represents only a report of a crime, that the number of incidents identified visually on the map may not accurately reflect the total number of incidents for the area and that attempts to derive a specific address are strictly prohibited.

Another limitation which might affect accuracy is if offenses are later determined to be unfounded.

Because the maps represent calls for service, this does not mean that an offence actually occurred. There might also be more than one call-for-service for any one incident. An example might be several observers may call 911 after witnessing a motor vehicle accident. As well, areas where there are a lot of people about will generally have higher reported calls for police assistance.

It is useful to think of how such visual maps can be part of a crime prevention initiative. They could be used to improve community awareness and safety, and could be the basis for Neighbourhood Watch initiatives, for example.

They could also be used to measure changes over time in the same geographic area, so as to best target community development resources.

They are an interesting development, not only in policing and public education, but also in the growing field of visual criminology.

Chris McCormick teaches Criminology at St. Thomas University. His column on crime and criminal justice appears every second Thursday.