Maggie Husak
Introduction to GIS
Assignment 7: Project Proposal
Project Description/Research Questions
I intend to use GIS to help determine whether there is equitable spatial distribution and
accessibility to neighborhood parks (or maybe playgrounds) in Houston, Texas. I am still in the
process of finalizing the variables by which to measure equity, as the literature suggests a variety
of demographic variables such as race, income, housing tenure, age (especially for playgrounds),
educational attainment, etc. While reviewing this question, I would like to also better understand
what types of developments seem to be compatible with open space planning (as Houston has no
zoning, it would be interesting to see what “naturally” abuts these open spaces.)
Questions:
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Is there an equitable distribution of open/recreational space in the city of Houston? (I
may choose to focus more specifically on neighborhood parks or playgrounds.)
o This may be determined by variables suggested by the literature, such as income,
race, housing tenure, percent owner occupied housing, car ownership, etc.
What types of land uses are found adjacent to parks in Houston?
What locations might be best suited for the development of new parks and playgrounds?
Annotated References
Lotfi, Sedigheh and Mohammad Javad Koohsari. 2009. Measuring objective accessibility to
neighborhood facilities in the city (A case study: Zone 6 in Tehran, Iran). Cities 26:133–140.
The authors review the geographical accessibility to public spaces (parks, etc.) in Tehran,
believing that such access is a crucial ingredient to a high quality of life of its citizens. Study
reviews this at the neighborhood scale using GIS and also endeavors to measure the level of
accessibility depending on a number of socio-economic characteristics of residents. The
authors discuss the methods by which one might define and measure accessibility using
qualitative and quantitative methods, discuss the possible options of measuring accessibility
using the following methods through GIS: container, coverage method, minimum distance,
travel cost, or gravity. The authors settle on minimum distance method using street network
distance, and each neighborhood unit was assigned a 1 or 0 depending on whether it fell
within the service area or not. Each neighborhood was assigned an index of “socio-economic
deprivation” based upon lvel of income, unemployment rate, car ownership, and building
quality in order to assess whether there was a higher proportion of already deprived
neighborhoods that also did not have access to community facilities. The reverse in fact was
true, these neighborhoods tended to have greater access.
Nicholls, Sarah. 2001. Measuring the accessibility and equity of public parks: a case study using
GIS. Managing Leisure 6:201–219.
Nicholls conducts a spatial analysis of the equitable distribution of parks in Byran, Texas.
She determines that radius method measuring “as the crow flies” distance is better than a
plain computation of ratios of parks to people, but does not account for important barriers to
accessibility (highways, rivers, etc). These are especially problematic for people traveling
with young children, as park-goers are likely to do. Additionally, some parks are only
accessible via a few entrances, and the radius method measures a distance from the closest
boundary point, even if it does not have an entrance nearby.
Nicholls uses the buffering technique, with “as the crow flies” and (local) street network
measurements the “service area” of an open space system, and then compares the
characteristics of people within and outside of the “service area” to determine levels of
accessibility and equity of public parks in Bryan, Texas. She is primarily concerned with
accessibility by walking, not parks which residents accessed by driving. Nicholls divides
parks up by categories according to their size and the level of service and then conducts the
analysis on two levels, just neighborhood parks and then all (neighborhood, mini, and
community) parks together. She uses ½ mile as the accessibility measurement.
Nicholls’ data layers include street network, boundary lines, park boundaries, park pedestrian
entrance points, socio-economic data in US Census blocks. (She used blocks to get as finely
tuned demographic data as possible.) When the buffer area is established, she compares the
mean of each variable she is studying (i.e. housing value, % non-white, % under 18, mean
housing value) of those blocks with their centroid within the buffer zone and those outside.
She finds an equitable distribution of parkland according to her analysis, but does determine
the city is overall deficient in the total amount of parkland it has for its entire population.
Oh, K., Jeong, S. 2007. Assessing the spatial distribution of urban parks using GIS. Landscape
Urban Planning.
The authors focus their study on park distribution in Seoul. They recognize that merely
calculating parks area per capita is no adequate measure of a park system that a city’s citizens
can regularly enjoy. A park’s accessibility is of prime importance when determining its
location. The authors recognize that examining a buffer with a street network analysis is best
method to really assess accessibility, and included additional measurements for pedestrian
impediments such as highways, intersections, etc. They use ½ mile as the accessibility
standard. They are not only concerned with residential access, but access by workers in the
commercial and industrial sectors as well. The authors are concerned primarily with park
accessibility for all citizens, and do not have any measurement as to whether the location of
parks is equitable according to socio-economic characteristics of the population.
Pearce, Jamie, Karen Witten and Phil Bartie. 2006. Neighbourhoods and health: a GIS approach
to measuring community resource accessibility. Journal of Epidemiol Community Health 60:389–
395.
The authors conduct a study in New Zealand to measure the impact that geographical
accessibility to community resources (including parks and recreational facilities) have on
individual health and wellbeing. Since the study focuses on access to community amenities
(which were theoretically driven), I found this to be relevant to my investigation of open
space accessibility. The authors also endeavor to assess whether there is an inequitable
distribution of community resources that may present unfavorable health and well-being
conditions for lower-income residents. Meshblocks, the smallest unit of New Zealand census
data, were used for this purpose. They used “population weighted centroids” for
measurement, a point that is at the center of the highest density for the meshblock, and a
network analysis to best assess travel times rather than straight line distance. Network
measurements accounted for road blocks and impediments which would decrease the
efficiency of travel. For park accessibility, the closest park boundary was considered the
accessibility point. Each meshblock was then assigned a quintile grouping indicating its level
of accessibility to a particular community resource (as determined by travel time by car).
Smoyer-Tomic, Karen E., Jared N. Hewko and M. John Hodgson. 2004. Spatial accessibility
and equity of playgrounds in Edmonton, Canada. The Canadian Geographer 48(3): 287–302.
The authors are concerned with measuring how equitable is the spatial accessibility of
playgrounds in Edmonton, Canada, assuming that underserved populations need more of such
amenities. The authors do not only study accessibility of playgrounds, but also measure
amenity quality. The authors use the minimum distance method (NEAR FUNCTION? distance to travel to closest playground) with a straight-line distance and using the centroid of
the neighborhood as one point of the line, and the coverage method (total number of
playgrounds within a ½ mile radius around a zip code centroid using the buffer technique;
summing the number of playgrounds in the buffer zone; calculating child populaton weighted
mean for each area.) Authors use city level census data at the neighborhood level, which
perfectly fits the study as “public playgrounds are allocated on a neighborhood basis.” Need
is assessed by age, income level, housing tenure, automobile ownership. The study finds that
“high-social-needs” neighborhoods do indeed have the best access to playgrounds, but access
to quality playgrounds is mixed.
Additional references
Crawford, David, et al.�2008. Do features of public open spaces vary according to
neighbourhood socio-economic status? Health & Place 14: 889–893.
Maroko, Andrew R., et al. 2009. The complexities of measuring access to parks and physical
activity sites in New York City: a quantitative and qualitative approach. International Journal of
Health Geographics 8:34
Timperio, A., et al.�2007. Is availability of public open space equitable across areas? Health &
Place 13:335–340.
Wolch, Jennifer, John P. Wilson and Jed Fehrenbach. 2002. Parks and Park Funding in Los Angeles:
An Equity Mapping Analysis. Los Angeles: USC Sustainable Cities Program and USC GIS Research
Laboratory. Available at: www.usc.edu/dept/geography/ESPE/.../publications_parks.pdf.
Possible Methods
Through my review of the literature and course materials, there are a few different methods I am
considering utilizing for my project. I think it actually may be a good idea to use more than one
method to attempt to answer the same question, as some of the study authors have done, in order
to help assess the different methods as well. Methods I am considering include:
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Buffer technique with network analysis to determine accessibility. Use census data to get
descriptive statistics on demographic variables both inside and outside of the buffer zone
to determine how equitable the access is.
Raster based analysis – possible method for determining placement for new
parks/playgrounds.
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Using block or block group center point, use “Near” function to assess straight line
minimum distance from to closest park/playground.
Use “select by location” to determine which types of parcels border parks/playgrounds.
Data Layers, Sources, and Minimum Accuracy Required
Data Layer Needed/Found
Harris County Greenway
Trails
Source (If found)
Harris County Architecture &
Engineering
Harris County Parks
Harris County Architecture &
Engineering
Park Locations
City of Houston Parks and
Recreation
Super Neighborhood
Boundaries
City of Houston Planning and
Development
Park Polygons
City of Houston Parks and
Recreation
Houston City Limit Boundary
City of Houston Planning and
Development
Major Roads
Extracted from STARMap
City of Houston Planning &
Development / HoustonGalveston Area Council
US Census 2000
US Census TIGER
US Census Block Groups or
Blocks Polygons
US Census 2000
Land Use/Parcels
Not found yet
Minimum Accuracy Required
Important, as park area is central to
the understanding of accessibility.
+- 10 feet.
Important, as park area is central to
the understanding of accessibility.
+- 10 feet.
Important, as park location is
central to the understanding of
accessibility. +- 10 feet.
Somewhat important, this will give
us a sense of larger neighborhood
boundaries. +- 30 feet.
Important, as park area is central to
the understanding of accessibility.
+- 10 feet.
Accuracy not hugely important,
this is merely to focus in on the
City of Houston for our study. +100ft.
Accuracy important, especially if
we are using street network
analysis. +- 10 feet.
Accuracy somewhat important
(although we already know we are
not going to get a great level of
accuracy here.) +- 20 ft
Accuracy important, as we hope to
get as finely tuned understand of
the demographics. +- 10 ft.
Accuracy somewhat important, as I
will be looking for land uses
adjacent to parks, and also try to
get a sense of residential
communities within a service area.
+- 20 ft