The Strategies of Geographical Profiling

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  1. What is the centre of gravity approach?
    • Pioneered by Kind (1987)
    • "Take a map of the area in which the 17 Yorkshire Ripper offences occurred and mark each location with a pin.
    • Next take and 18th pin and join it to each of the 17 locations by a piece of thread.
    • That location of the 18th pin which minimizes the amount of thread required is the centre of the 17 offences."
  2. What are the problems with the centre of gravity approach?
    • Provide only a single piece of information 
    • Can be distorted by spacial outliers
    • Sometimes locations do not follow the rules of measures of central tendency
  3. What is the circle hypothesis?
    • Only used if the case suggests the offender is operating from a home base
    • Offender is contained within a defined area 
    • Offender will move as little as possible but far enough away to avoid suspicion 
    • The home is central to the crime location

    • Home range: area of activity space around offender's home
    • Criminal range: area of offending between two offence sites furthest apart
  4. What is the marauder type?
    • Canter & Larkin (1993)
    • Commit crimes with their home base central
    • Leave the house and travel to commit
    • Arsonists more likely to follow this pattern (82%) and 71% of Australian rapists (Kocsis & Irwin, 1997)

    87% of rapists were found to be marauders
  5. What is the commuter type?
    • Canter & Larkin (1993)
    • Offences are committed in areas believed to be unrelated to the area of residence and untraceable back there 
    • Areas for crime can be established as well as areas for their everyday lives
    • Burglars more likely to adopt this strategy (Meaney, 2004)
    • Athough 50/50 was found by Kocsis et al (2002) and at least 5 crimes were required before a perimeter could be established
  6. What are probability distance strategies?
    • Assume that the offender's crime site location is the same as their activity space and location 
    • A mathematical function is applied to each crime scene to generate a likelihood surface that indicated the probability of an offender living in that area
  7. What are distance decay functions?
    • Functions that state that the more geographically distance a location, the lower the probability of crime occurring there 
    • Calibrated using a calibration dataset, comprised of details of crimes committed in the area and travel patterns 
    • Each area has different travel patterns
Card Set:
The Strategies of Geographical Profiling
2015-04-05 17:25:12
Psychology Criminology
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