Exploring the use of GIS in Crime Mapping in Allegan County, Michigan

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Exploring the use of GIS in Crime
MappinginAllegan County, Michigan

• Neil Besteman
• Grand Valley State University
• Geography and Planning Department
• November 16, 2004

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Background InformationAllegan, County

• Geography
• Allegan County is located in the south west part
  of Lower Michigan.  It is approximately 827
  square miles with 25 miles of coast line along
  Lake Michigan.  It is the 18th largest county in
  Michigan and has 24 townships.
• Population of 105,665 as of 2000 Census.
• The County is still mostly rural in nature, and
  still maintains an agriculture and tourist based
  economy, however trends are toward more light
  industry and technology which has translated into
  Allegan County being in one of the fastest
  growing regions of the state. Allegancounty.org

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Background InformationCrime

• Crime Information
• The Crime Control Industry and the Economy
• Government expenditures for "justice" have been
  growing at an average rate of 8.1 a year since
  1982. A staggering 36 billion in 1982 grew 309
  to 147 billion in 1999. Correcting for
  inflation, that's an increase of 145.

Graphs and quote are part of The Prison Index
(2003) by Peter Wagner. Information can be found
at www.prisonpolicy.org

• Allegan County Crime
• 5,453 crime reports taken within Allegan County
  between October, 2003 and September, 2004.

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Purpose

• Explore the use GIS in mapping crime in Allegan
  County, Michigan.
• Determine relationships of crime levels to social
  factors that may be influenced by governmental
  policy.
• Depict areas of increased criminal activity or
  hotspots for use of local agencies in crime
  analysis and prevention.

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Data Selection Programs Used

• Representative Data
• Crimes Burglaries
• Social tendency Median Income by Household
• Computer Programs Used
• Hotspots maps - Mapinfo
• Correlation of data groups SPSS
• Visual representation within slides - ArcView

Graph is part of The Prison Index (2003) by
Peter Wagner. Information can be found at
www.prisonpolicy.org
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Data Source Description
Reported Crimes

• Raw data source
• Crimes - Allegan County AS400 database files
• Median Income per Household by Blockgroup - 2000
  Census American Factfinder
• Blockgroup and Street layers - Framework data
  from Center for Geographic Information version 4b
• Recognized problems
• Census data is dated
• Difficulty geocoding crime data into Blockgroups

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Methods Model,Correlation
Average Income per Household by
Block-Group (polygon)
Income Census Data (table)
Correlation Model
Results
Census Block-Group (polygon)
Correlation Results
Correlation (Spearmans rho)
Crimes Per Block-Group (polygon)
1 Year of Crime Data (table)
Scrub Data Select Crimes (burglaries)
Geocode Crime Locations (point)
Hotspots
Rasterize
Hotspots Model
Street Framework (line)
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Methods

• Geocoded Burglaries layer over Median Income per
  Household by Blockgroup

255 of 270 Burglaries Mapped (94.4)
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Correlation Results
Scatterplot
Pearson Correlation
Outlier
Total Burglaries
Initially performed Pearson Correlation with and
without noted outlier resulting in no significant
correlation. Performed Spearmans Correlation
(distribution free test not affected by outliers)
resulting in no significant correlation.
Spearmans Correlation
Conclusion No significant correlation between
Median Income per Household and number of
burglaries within corresponding Blockgroups.
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Methods

• Burglaries over Population Levels

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Additional Correlation Results
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Methods Model,Hotspots
Average Income per Household by
Block-Group (polygon)
Income Census Data (table)
Correlation Model
Census Block-Group (polygon)
Correlation Results
Correlation (Spearmans rho)
Crimes Per Block-Group (polygon)
1 Year of Crime Data (table)
Scrub Data Select Crimes (burglaries)
Geocode Crime Locations (point)
Hotspots
Rasterize
Hotspots Model
Street Framework (line)
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Burglary Hotspots 3D Map
Monterey Lake (cause of outlier on scatterplot)
Holland
Allegan
Saugatuck
Plainwell
Lake Michigan
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Violent Crime Hotspots 3D Map
Holland
Saugatuck
Allegan
Plainwell
Lake Michigan
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Continuing Steps

• Present information to local law enforcement,
  Health Department and Social Services to
  determine data and analysis that they would like
  to see and use.
• Coordinate with law enforcement to take GPS
  locations when investigating crimes.
• Improve data input protocol through education and
  programming.
• Coordinate with Allegan County IT to receive
  appropriate updates to the data.

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Use of Geographic Information Systems in Crime
Analysis

• Crime mapping can be used as a compliment to
  other forms of crime analysis.
• Crime mapping has a unique (visual) role in
  presenting integrated views of data and products
  of analysis
• GIS-derived information supports decision making
  of variety of stakeholders who need to answer
  questions on
• how crime and disorder are manifested socially,
  spatially and temporally
• The social and environmental risk factors that
  account for them and
• The impact such crime and disorder has on the
  community that experiences them.

Book Review of Mapping and analysing crime data
lessons from research and practice (2001)Edited
by Hirschfield, A. and Bowers, K. Taylor and
Francis, London Located in the Journal of the
Urban and Regional Information Systems
Association Vol.16 No.1 2004.