Mental Maps

    ◦ Over time, making repetitive journeys to various
      locations gives us knowledge of the routes and
...
Journey an offender travels when he commits

    a crime
    Generally measured as the distance between

    the offende...
Crimes against persons, such as

    homicide, assault, and rape, occur closer to
    home than property crimes, such as ...
Burgled
                                   Homes


                                             X
    X                   ...
It is important to note that offenders do

    commit crimes within their buffer zone;
    however, there may be areas ou...
Police investigation strategy that uses the

    locations in a connected crime series to narrow
    the search for likel...
Searching methods

    ◦ Hunter (or marauder)
       sets out from his home specifically to find a victim
    ◦ Poacher ...
Methods of attack

    ◦ Raptor
      attacks the victim upon encounter
    ◦ Stalker
      follows the victim away fro...
Investigative Strategies

    ◦ Prioritizing records from the various computerized
      police files
    ◦ Prioritize ar...
Software Available

    ◦ RIGEL
       Developed by Environmental Criminology Research Inc. (ECRI)
        of Vancouver,...
Fundamentalsof Crime Mapping 4
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Fundamentalsof Crime Mapping 4

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Fundamentals of crime mapping chapter 4

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Fundamentalsof Crime Mapping 4

  1. 1. Mental Maps  ◦ Over time, making repetitive journeys to various locations gives us knowledge of the routes and characteristics of these places Activity space  ◦ The well-known areas, those places visited frequently and the routes that connect these areas Awareness space  ◦ There are also locations that, while we do not regularly frequent them, we still know about them Target backcloth  ◦ The distribution of targets in the environment
  2. 2. Journey an offender travels when he commits  a crime Generally measured as the distance between  the offender’s home and the location of his crime AV E R AG E O F CR I M E C AT E GO R Y T R IPS M E D IA N* M O DE ** A GG . AS S AU L T 1 . 18 1. 4 9 0. 2 0 AR S O N 1 . 32 0. 5 3 0. 5 9 AU TO T H E F T 2 . 88 2. 4 0 1. 8 5 BU R GL A RY 2 . 34 1. 1 0 2. 7 5 D R UG O F F E N S E S 2 . 27 1. 5 3 8. 4 1 M UR D E R 2 . 38 1. 7 5 1 0. 9 5 R AP E 1 . 35 1. 7 0 N/ A RO B BE RY 3 . 23 1. 9 5 2. 8 3 T H EF T 3 . 18 1. 8 6 0. 5 3 * & ** C alcu late d on n on -z er o d ista nc es on ly
  3. 3. Crimes against persons, such as  homicide, assault, and rape, occur closer to home than property crimes, such as larceny and burglary (Brantingham & Brantingham, 1981). Overall average about 2 miles  Distance decay  ◦ Probability decays or drops off as distance from the offender’s residence increases
  4. 4. Burgled Homes X X X X X Suspect’s X Home and Buffer Zone X
  5. 5. It is important to note that offenders do  commit crimes within their buffer zone; however, there may be areas outside their buffer zone where they commit more crimes. The buffer zone represents an area of reduced activity not an area of “no” criminal activity
  6. 6. Police investigation strategy that uses the  locations in a connected crime series to narrow the search for likely suspects Manage large amounts of information  Help focus limited resources on the most likely  area of offender residence Crime series  ◦ a set of crimes believed to have been committed by the same offender.
  7. 7. Searching methods  ◦ Hunter (or marauder)  sets out from his home specifically to find a victim ◦ Poacher (or commuter)  specifically sets out to find a victim, but his search is from a location other than his home ◦ Troller  opportunistically encounter a victim during normal activities ◦ Trapper  set up a situation in which victims come to them
  8. 8. Methods of attack  ◦ Raptor  attacks the victim upon encounter ◦ Stalker  follows the victim away from the encounter point then attacks ◦ Ambusher  attacks a victim that he has lured to a location he controls
  9. 9. Investigative Strategies  ◦ Prioritizing records from the various computerized police files ◦ Prioritize areas for directed police patrols or area canvasses ◦ Direct community mailings and/or conduct a media campaign
  10. 10. Software Available  ◦ RIGEL  Developed by Environmental Criminology Research Inc. (ECRI) of Vancouver, British Columbia, Canada, uses the Criminal Geographic Targeting algorithm invented by Dr. Kim Rossmo in 1991 to produce a probability map ◦ Dragnet  created by Dr. David Canter of the University of Liverpool, England, uses a negative exponential mathematical function to produce a probability map  Crime Analysis Unit Developer Kit free ◦ Crime Stat III (JTC only)  created by Ned Levine and & Associates of Houston, Texas  Free through NIJ

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