Relocating San Francisco Police Stations to Serve High-Crime...
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POSTER TEMPLATE BY: www.PosterPresentations.com Relocating San Francisco Police Stations to Serve High-Crime Areas Adam Visconti & Yun Tara Zhang Geography C188: University of California, Berkeley Background Flowchart of Data Processing Steps References At present, San Francisco ranks in the top quartile of cities in terms of crime per population (1), below cities of comparable size including San Jose, Seattle, and New York City. Additionally, the crime clearance rate for violent and property crimes has stayed roughly stable at 32% and 11% respectively over the last 20 years (2). The crime clearance rate for violent and property crimes in San Francisco ranks within the bottom five of major metropolitan areas according to a study by The Emergency Response and Research Institute. Additionally, the SF clearance rate for solving murders, rapes, robberies, shootings, stabbings and other serious assaults between 1996 and 2000 ranks last within major US metropolitan areas (3). The average police response time to a priority call rates at 6 minutes, below other comparable metropolitan areas (4). At the request of the Safety Network, a local community-based organization which develops and advocates for grassroots strategies to improve public safety, we were requested to analyze crime rates within San Francisco. Our analysis will answer the following questions: 1) Which areas of San Francisco experience the most severe levels of crime? 2) Is the location of the San Francisco Police Department’s stations compatible with the spatial pattern of crime in the City? 3) How can the San Francisco Police Department relocate their police stations to better respond to crime within San Francisco? Non-homicide crime data from 5/01/2009 to 11/11/2009 was downloaded from San Francisco Crimespotting (http://sanfrancisco.crimespotting.org) which sources crime reports from the San Francisco Police Department CrimeMAPS website (http:// www.sf-police.org/index.aspx?page=1618). Shapefiles of San Francisco police station locations and San Francisco street network were downloaded from the Geography C188 course website at UC Berkeley. Weights for severity of crime were derived from the California State Penal Code average recommendations for felony and misdemeanor crimes (5). Weights for acuity were derived from a prioritization scheme utilized by the Arlington, TX police department (6). Data Sources Our analysis strategy involved several steps. The first step was to create a density raster file for all non-homicide crime incidents from 5/01/2009 to 11/11/2009, weighted by the severity of the crime and the urgency of police response to the crime. The second step involved calculating the network service area of all 10 active San Francisco police stations within certain distance parameters from the station (1/8, 1/4, 1/2, 3/4, and 1 mile radius). The third step involved calculating the total percent of weighted crime within 1 mile network of all active police stations. The fourth step involved repositioning the 10 police stations to areas of high-crime and recalculating the percent of weighted crime within a 1 mile network radius of each of the new station locations. Conclusions Through our analysis, we provide a clear graphical interpretation of the severity and acuity of crime within San Francisco. The neighborhoods most affected by crime include: the Tenderloin, South of Market Area (SOMA) Civic Center, Inner Mission, Bayview / Hunters Point, and Visitacion Valley. The present location of police precincts covers 68.91% of crime within a one mile network. Our proposed relocation of police precinct would allow for an additional 8.52% of crime to be covered within police response networks. However, this relocation concentrates all active police stations to the eastern half of San Francisco. Previous attempts at removing police precincts in the Western half of the City have met stiff resistance, and thus the political feasibility of this reorganization is low. 1. F.B.I. "Crime in the United States 2007." Accessed 11/15/2009. Available at http://os.cqpress.com/citycrime/CityCrime2008_Rank_Rev.pdf 2. “San Francisco Community Indicators, Rates of Violent and Property Crimes Solves.” Accessed 11/15/2009. Available at http://www.sfgov.org/ wcm_controller/community_indicators/publicsafety/crimesclearancerate/crimeclearancerate.htm 3. David Parrish & Jaxon Van Derbeken. “SFPD dead last in solving violent crime.” San Francisco Chronicle. Sunday, May 19, 2002. Accessed 11/16/2009. Available at http://www.sfchroniclemarketplace.com/cgibin/article.cgi?f=/c/a/2002/05/19/MN20982.DTL#ixzz0Y5kvF5Kfhttp:// www.sfchroniclemarketplace.com/cgi-bin/article.cgi?f=/c/a/2002/05/19/MN20982.DTL#ixzz0Y5khhLJ6 4. “San Francisco Community Indicators: Average time from receipt of top priority call to police arrival on scene.” Available at http://www.sfgov.org/site/ controller_page.asp?id=30343 5. “California Judges Bench Guide 75 – Misdemeanor and Felony Sentencing.” California Center for Judicial Education and Research 6. “Police Response to 911 Calls.” Arlington Police Department On-Line. Available at www.arlingtonpd.org/index.asp?nextpg=911response.h Research Questions Overview of Process 1. Create point shapefiles for crime incidents by crime category 2. Use spatial analyst tool to create 45 individual raster files representing the simple density of crime incidents within 1/8 mile of each cell for each crime category 3. Create one aggregate density raster of crime incidents weighted by severity and acuity of crime using the raster calculator tool. Aggregate density raster = ∑ (weight i x density raster i ) Where weight i = (severity i x acuity i ) and, i = crime category (e.g. arson, rape, theft…etc) 4. Using SF streets as our network dataset, create polygons representing the network service area for each of 10 San Francisco police stations. We specified default breaks of 1/8 mile, 1/4 mile, ½ mile and 3/4 mile away from each police station. 5. Sum the values of the aggregate weighted crime raster which fell underneath the 1 mile radius service area overlays for each active police station. The percentage of weighted crime covered by each active police station = sum of raster cells within each service area / total sum of raster cells in SF. 6. Relocate the 10 police stations and recalculate the network service area analysis and the percentage of weighted crime covered by each relocated police station Proposed Patrol Police Stations Percent of Weighted Crime Covered by Service Area Nob Hill Station (Pacific and Hyde) 13.32% SOMA Station (4th St. and Mission) 21.59% Pacific Heights Station (Scott and Jackson) 5.21% Hayes Valley Station (Fell and Webster) 8.92% Inner Mission Station (20th St. and Treat) 10.62% Cole Valley Station (17th St. and Cole) 2.51% Bayview / Hunters Point Station (Oakdale and Lane) 5.42% Visitation Valley Station (Sawyer and Raymond) 3.04% Balboa Park Station (Ocean and Alemany) 3.76% Bernal Heights Station (Holly Park and Newman) 3.04% Proposed Percent of Crime Actively Patroled 77.43% Absolute Percentage Change 8.52% Percent Increase Change 12.36% Active Patrol Police Stations Percent of Weighted Crime Covered by Service Area Mission Police Station 12.71% Bayview Police Station 5.39% Tenderloin Task Force Station 30.10% Ingleside Police Station 2.21% Park Police Station 2.69% Potrero Police Station 1.82% Richmond Police Station 1.47% Taraval Police Station 1.07% Central Police Station 5.78% Northern Police Station 5.66% Percent of Crime Actively Patroled 68.91% Step 5. Step 4. Step 2. Step 1. Current Police Locations with Weighted Crime Density Proposed Police Locations with Weighted Crime Density Weighted Crime Density in San Francisco 3-D View of Proposed Police Locations Crime Description Severity Acuity Weight Aggravated Assault 6 3 18 Aggravated Assault (Deadly Weapon) 12 4 48 Arson 36 2 72 Battery 6 2 12 Burglary 36 3 108 Carjacking 60 4 240 Child Abuse 48 3 144 Child Molesting 24 2 48 Domestic Abuse 12 2 24 Forgery 6 1 6 Homicide - Attempt 80 5 400 Narcotics - Cocaine - Pos 12 2 24 Narcotics - Cocaine - Sale 36 2 72 Narcotics - Cocaine - Trans 12 2 24 Narcotics - Crack - Pos 12 2 24 Narcotics - Crack - Sale 12 2 24 Narcotics - Heroin - Pos 8 2 16 Narcotics - Heroin - Sale 28 2 56 Narcotics - Heroin - Trans 8 2 16 Narcotics - Marijuana - Pos 0.25 1 0.25 Narcotics - Marijuana - Sale 6 1 6 Narcotics - Marijuana - Trans 0.25 1 0.25 Narcotics - Meth - Pos 8 2 16 Narcotics - Meth - Sale 40 2 80 Narcotics - Meth - Trans 10 2 20 Narcotics - Other - Pos 4 1 4 Narcotics - Other - Sale 8 1 8 Narcotics - Other - Trans 8 1 8 Narcotics - Paraphernalia - Pos 2 1 2
Transcript of Relocating San Francisco Police Stations to Serve High-Crime...
POSTER TEMPLATE BY:
www.PosterPresentations.com
Relocating San Francisco Police Stations to Serve High-Crime Areas Adam Visconti & Yun Tara Zhang
Geography C188: University of California, Berkeley
Background Flowchart of Data Processing Steps
References
At present, San Francisco ranks in the top quartile of cities in terms of crime per population (1), below cities of comparable size including San Jose, Seattle, and New York City. Additionally, the crime clearance rate for violent and property crimes has stayed roughly stable at 32% and 11% respectively over the last 20 years (2). The crime clearance rate for violent and property crimes in San Francisco ranks within the bottom five of major metropolitan areas according to a study by The Emergency Response and Research Institute. Additionally, the SF clearance rate for solving murders, rapes, robberies, shootings, stabbings and other serious assaults between 1996 and 2000 ranks last within major US metropolitan areas (3). The average police response time to a priority call rates at 6 minutes, below other comparable metropolitan areas (4).
At the request of the Safety Network, a local community-based organization which develops and advocates for grassroots strategies to improve public safety, we were requested to analyze crime rates within San Francisco. Our analysis will answer the following questions:
1) Which areas of San Francisco experience the most severe levels of crime?
2) Is the location of the San Francisco Police Department’s stations compatible with the spatial pattern of crime in the City?
3) How can the San Francisco Police Department relocate their police stations to better respond to crime within San Francisco?
Non-homicide crime data from 5/01/2009 to 11/11/2009 was downloaded from San Francisco Crimespotting (http://sanfrancisco.crimespotting.org) which sources crime reports from the San Francisco Police Department CrimeMAPS website (http://www.sf-police.org/index.aspx?page=1618).
Shapefiles of San Francisco police station locations and San Francisco street network were downloaded from the Geography C188 course website at UC Berkeley.
Weights for severity of crime were derived from the California State Penal Code average recommendations for felony and misdemeanor crimes (5). Weights for acuity were derived from a prioritization scheme utilized by the Arlington, TX police department (6).
Data Sources
Our analysis strategy involved several steps. The first step was to create a density raster file for all non-homicide crime incidents from 5/01/2009 to 11/11/2009, weighted by the severity of the crime and the urgency of police response to the crime. The second step involved calculating the network service area of all 10 active San Francisco police stations within certain distance parameters from the station (1/8, 1/4, 1/2, 3/4, and 1 mile radius). The third step involved calculating the total percent of weighted crime within 1 mile network of all active police stations. The fourth step involved repositioning the 10 police stations to areas of high-crime and recalculating the percent of weighted crime within a 1 mile network radius of each of the new station locations.
Conclusions Through our analysis, we provide a clear graphical interpretation of the severity and acuity of crime within San Francisco. The neighborhoods most affected by crime include: the Tenderloin, South of Market Area (SOMA) Civic Center, Inner Mission, Bayview / Hunters Point, and Visitacion Valley. The present location of police precincts covers 68.91% of crime within a one mile network. Our proposed relocation of police precinct would allow for an additional 8.52% of crime to be covered within police response networks. However, this relocation concentrates all active police stations to the eastern half of San Francisco. Previous attempts at removing police precincts in the Western half of the City have met stiff resistance, and thus the political feasibility of this reorganization is low.
1. F.B.I. "Crime in the United States 2007." Accessed 11/15/2009. Available at http://os.cqpress.com/citycrime/CityCrime2008_Rank_Rev.pdf 2. “San Francisco Community Indicators, Rates of Violent and Property Crimes Solves.” Accessed 11/15/2009. Available at http://www.sfgov.org/
wcm_controller/community_indicators/publicsafety/crimesclearancerate/crimeclearancerate.htm 3. David Parrish & Jaxon Van Derbeken. “SFPD dead last in solving violent crime.” San Francisco Chronicle. Sunday, May 19, 2002. Accessed 11/16/2009.
Available at http://www.sfchroniclemarketplace.com/cgibin/article.cgi?f=/c/a/2002/05/19/MN20982.DTL#ixzz0Y5kvF5Kfhttp://www.sfchroniclemarketplace.com/cgi-bin/article.cgi?f=/c/a/2002/05/19/MN20982.DTL#ixzz0Y5khhLJ6
4. “San Francisco Community Indicators: Average time from receipt of top priority call to police arrival on scene.” Available at http://www.sfgov.org/site/controller_page.asp?id=30343
5. “California Judges Bench Guide 75 – Misdemeanor and Felony Sentencing.” California Center for Judicial Education and Research 6. “Police Response to 911 Calls.” Arlington Police Department On-Line. Available at www.arlingtonpd.org/index.asp?nextpg=911response.h
Research Questions
Overview of Process
1. Create point shapefiles for crime incidents by crime category
2. Use spatial analyst tool to create 45 individual raster files representing the simple density of crime incidents within 1/8 mile of each cell for each crime category
3. Create one aggregate density raster of crime incidents weighted by severity and acuity of crime using the raster calculator tool. Aggregate density raster = ∑ (weighti x density rasteri) Where weighti = (severityi x acuityi) and, i = crime category (e.g. arson, rape, theft…etc)
4. Using SF streets as our network dataset, create polygons representing the network service area for each of 10 San Francisco police stations. We specified default breaks of 1/8 mile, 1/4 mile, ½ mile and 3/4 mile away from each police station.
5. Sum the values of the aggregate weighted crime raster which fell underneath the 1 mile radius service area overlays for each active police station. The percentage of weighted crime covered by each active police station = sum of raster cells within each service area / total sum of raster cells in SF.
6. Relocate the 10 police stations and recalculate the network service area analysis and the percentage of weighted crime covered by each relocated police station
Proposed Patrol Police Stations Percent of Weighted Crime Covered by Service Area
Nob Hill Station (Pacific and Hyde) 13.32% SOMA Station (4th St. and Mission) 21.59% Pacific Heights Station (Scott and Jackson) 5.21% Hayes Valley Station (Fell and Webster) 8.92% Inner Mission Station (20th St. and Treat) 10.62% Cole Valley Station (17th St. and Cole) 2.51% Bayview / Hunters Point Station (Oakdale and Lane) 5.42% Visitation Valley Station (Sawyer and Raymond) 3.04% Balboa Park Station (Ocean and Alemany) 3.76% Bernal Heights Station (Holly Park and Newman) 3.04% Proposed Percent of Crime Actively Patroled 77.43% Absolute Percentage Change 8.52% Percent Increase Change 12.36%
Active Patrol Police Stations Percent of Weighted Crime Covered by Service Area
Mission Police Station 12.71% Bayview Police Station 5.39% Tenderloin Task Force Station 30.10% Ingleside Police Station 2.21% Park Police Station 2.69% Potrero Police Station 1.82% Richmond Police Station 1.47% Taraval Police Station 1.07% Central Police Station 5.78% Northern Police Station 5.66% Percent of Crime Actively Patroled 68.91%
Step 5.
Step 4.
Step 2.
Step 1.
Current Police Locations with Weighted Crime Density
Proposed Police Locations with Weighted Crime Density
Weighted Crime Density in San Francisco
3-D View of Proposed Police Locations
Crime Description Severity Acuity Weight Aggravated Assault 6 3 18
Aggravated Assault (Deadly Weapon) 12 4 48 Arson 36 2 72 Battery 6 2 12 Burglary 36 3 108 Carjacking 60 4 240 Child Abuse 48 3 144 Child Molesting 24 2 48 Domestic Abuse 12 2 24 Forgery 6 1 6 Homicide - Attempt 80 5 400 Narcotics - Cocaine - Pos 12 2 24 Narcotics - Cocaine - Sale 36 2 72 Narcotics - Cocaine - Trans 12 2 24 Narcotics - Crack - Pos 12 2 24 Narcotics - Crack - Sale 12 2 24 Narcotics - Heroin - Pos 8 2 16 Narcotics - Heroin - Sale 28 2 56 Narcotics - Heroin - Trans 8 2 16 Narcotics - Marijuana - Pos 0.25 1 0.25 Narcotics - Marijuana - Sale 6 1 6 Narcotics - Marijuana - Trans 0.25 1 0.25 Narcotics - Meth - Pos 8 2 16 Narcotics - Meth - Sale 40 2 80 Narcotics - Meth - Trans 10 2 20 Narcotics - Other - Pos 4 1 4 Narcotics - Other - Sale 8 1 8 Narcotics - Other - Trans 8 1 8 Narcotics - Paraphernalia - Pos 2 1 2
