4. Importance of City Planning - Dr. Toe Aung Ycdc
Revised SWUC Slides
1. Creating a Walkability Surface for
Maricopa County
Parul Singh and Madison Davis
ASU MAS-GIS students
Co-Authors: Marc Adams, Jane Hurley, Lu Hao
Funding Source #: R01CA198915
2. Presentation Objective
To share the the steps taken and tools used to create a
geographic surface of walkability for Maricopa County
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3. Overview
• Background on Walkability and WalkIT Arizona Study
• Four Components of the Walkability Index:
o Net Residential Density
o Intersection Density
o Transit Density
o Land Use Mix (Entropy)
• Results and Significance
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4. Why is Walkability important?
U.S. Department of Health and Human
Services. September 2015
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Vice Admiral Vivek Hallegere Murthy,
Surgeon General of the United States
5. WalkIT Arizona Study
“to test the effectiveness of interventions using
physical activity trackers, goal setting,
motivational text messages, monetary incentives
and health education to promote physical activity
behaviors...”
“in high and low walkable
communities”
Principal Investigator
Marc Adams, PhD, MPH
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6. International Physical Activity and
Environment Network (IPEN) Study
IPEN GIS templates guided decisions to quantify built environment attributes for
physical activity
Templates include +100 pages of definitions, recommendations
www.ipenproject.org
Adams, Frank et al., 2015 Int’l J of Health Geographics
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8. Calculating Walkability
• 4 components, each is a surface
• First find raw scores for each component
• Walkability Index = [ (z-score of net residential density)
+ 2*(z-score of intersection density)
+ (z-score of transit density)
+ (z-score of land use mix)]
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13. Preliminary Steps
• Data Acquisition
o Maricopa County Assessor's Office
o Maricopa Association of Governments (MAG)
o Valley Metro
o U.S. Census Bureau
• Prep for use in context
o Projection: NAD 1983 HARN StatePlane Arizona Central FIPS 0202 (Meters)
• PUCs Reclassification (2251 down to 5)
o Main categories:
residential
retail
office
entertainment
civic 13
15. PUCs Reclassification
● Entertainment
○ bars, night clubs, theaters, museums
● Civic/ institutional
○ educational, religious, health, governmental, police, military facilities
● Multi-use codes (mixed-use)
○ Store & Office/Apartment
○ Office & Residence
■ double/ triple counted
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16. Unit of Analysis
• Census Block Groups
o Aligns with population estimate in IPEN templates
• 100 Meter buffer
o Captures walkability/built environment features on edges
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19. Net Residential Density
• Ratio of residential housing units: residential land area in the buffer
o Residential= permanent, majority of the year, not easily moved
housing/dwelling units
o Includes single and multi family use
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20. Net Residential Density
• High Density = many units in area
• Low Density = units spread out
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Imagery: Google, Map Data, Digital Globe, 2016
21. Net Residential
Density
• Layer of all
residential parcels
o ~1.3 million parcels
• Includes Land Area
and Housing Unit
count fields
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22. • Assign parcels to buffered
block groups
Net Residential Density
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26. Intersection Density
• Ratio of intersections : land area
• Intersection: 3 or more walkable road segments intersect
• High Density = Many walkable intersections
• Low Density = Few walkable intersections
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27. Intersection Density
Roads Included:
1. Neighborhood Streets
2. Byway - single lane of traffic in
each direction
3. Pedestrian Trail
4. Pedestrian Passageway
5. Rural Road
6. City Streets
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Roads Excluded:
1. Interstate highway
2. Ramps
3. Unpaved Roads
4. Limited Access Highways
5. Freeways
6. Expressway
34. Transit Density
• Ratio of transit stops: land area
• Transit stops include bus and light rail
• Considered how many buses stop at each ‘physical’ stop
• High Transit Density = many transit stops
• Low Transit Density = few transit stops
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39. Land Use Mix
• Calculation of entropy of land use types in block group buffer
• Raw Score always between 0 and 1
o 0 indicates only one land use present
o 1 indicates a perfectly even distribution of all land uses across the block
group buffer
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40. Land Use Mix
• Repeat merge and summarize processes described to get the sum of land or
floor area in each block group
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LandUseMix.gdb
ParcelArea_Office
ParcelArea_Retail
ParcelArea_Civic
ParcelArea_Entertainment
LivableArea_Residential
43. Walkability Index
Walkability Index = [ (z-score of net residential density) + (z-score of intersection density) + (z-
score of transit density) + (z-score of retail floor area ratio) + (z-score of land use mix)]
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44. Z- Score
Net Residential Density
Intersection Density
Transit Density
Land Use Mix
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Lowest Highest
53. Advantages of using GIS
• Analysis on Macroscale
• Use existing data
• Map Creation
• Patterns are clearly observed
• Help to select neighborhoods to test the effectiveness of the physical activity
intervention
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54. Conclusion
• Able to target recruiting efforts to high and low walkable areas
• Gather participants for the WalkIT Arizona Research Study
Next Steps
● Virtual truth to make sure the surface makes sense
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58. Data Versions:
Maricopa County Block Groups, 2010 U.S. Census
Parcels, Maricopa County Assessor’s Office, 2015
Light Rail and Transit Stops, Valley Metro, 2015
Roads, U.S. Census TIGER/Line, 2015
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Editor's Notes
Drs. Adams and Frank co-developed a 107 page document of GIS templates for measuring built environment features and walkability while coordinating 12 countries in the IPEN Adult study.
Area 9,224 mi²
Population 4.009 million (2013)
***Service Layer Credits****
Sources of data and year
--2015 parcel data
-Residential: non-movable dwelling, live permanently or mostly
dormitory( and other school-related units)
-retail: shopping malls including strip malls, neighborhood, community, regional shopping malls
car wash facilities included becuz they come with some food stores and groceries.
-Office: school and business administration,
-medical services：include clinic and emergency but hospital. Parcels for hospital use have large portion of parking area.
-civic:
a). both public and private civic/ institutional counted in.
b).residential and offices for religious use counted as religious use. when classifying the land use category, we look at the
larger category instead of the subdivided type under the large one.
-Entertainment: location for certain types of social activities, no recreational facilities for physical activities included
-SFR status unknown: those parcels are likely in the abandoned or severely degraded (totally/partially vacant)condition, thus we
define them as vacant land.
-Food-related: exclude the multi-use with restaurants, such as hotels, resorts, shopping malls, office building.
How many codes altogether? -- 2251
600 to 3,000 people
1,257,450 Parcels in 2111 block groups
***Service Layer Credits****
Secondary roads are main arteries, usually in the U.S. Highway, State Highway or County Highway system. These roads have one or more lanes of traffic in each direction, may or may not be divided, and usually have at-grade intersections with many other roads and driveways. They often have both a local name and a route number.
Generally a paved non-arterial street, road, or byway that usually has a single lane of traffic in each direction. Roads in this feature class may be privately or publicly maintained. Scenic park roads would be included in this feature class, as would (depending on the region of the country) some unpaved roads.
A path that is used for walking, being either too narrow for or legally restricted from vehicular traffic.
A path that is used for manual or small, motorized bicycles, being either too narrow for or legally restricted from vehicular traffic.
Note: stops are counted by routes at each stop. A block group with 5 ‘physical’ stops but 1 stop has 2 different routes makes 4+2 = 6 transit stops in the bloNote: stops are counted by routes at each stop. A block group with 5 ‘physical’ stops but 1 stop has 2 different routes makes 4+2 = 6 transit stops in the block group
***Service Layer Credits****
NO AIRPORTS: 040131138001 (BLOCK GROUP)
***Service Layer Credits****
***Service Layer Credits****
(Advantages of using GIS both as an approach to walkability and in research)
GIS allows us to work on a Macroscale to create a walkability surface using the existing data sources from Maricopa County Assessor’s Office, Valley Metro and Census
Makes it easy to display the results on the maps-deeper insights and visualize: this allows the research study to recruit from high/low walkable communities to test effectiveness of the physical activity intervention
GIS provides a very effective means for graphically conveying complex information. Layouts created with a GIS are extremely useful when included in reports and presentations.
