BACKGROUND & LITERATURE
Implementing and Evaluating Spatial Segregation Measures
Using Geographic Information Systems (GIS) Technology
The initial research question of this project was triggered by the paper by Morrill (1991), which clearly demonstrated that the D segregation index is aspatial in nature such that it cannot handle the so-called the "checkerboard" problem. The "checkerboard" problem is simply a highly fragmented population landscape in which each areal unit is exclusively occupied by only one population group and the D index cannot differentiate such a pattern from a two-region pattern, in which each group compleleted occupies one region. Morrill (1991) suggested a modification of the D index by incorporating a spatial or neighborhood element to introduce the D(adj) index. The author further enhanced the D(adj) index by incorporating more spatial components (Wong, 1993).
The above indices are for two-group comparison. Multi-group comparison seems to be more realistic. The multi-group version of D, D(m) was introduced before (Morgan, 1975; Sakoda, 1981), but it shares the same limitation with D from a spatial perspective. The author launched a series of analysis to develop the spatial version of the multi-group index (1998) and additional (local) indices (1996, 2002).
Unfortunately, all these indices are difficult to use because spatial information is needed in the computation. These spatial indices were not the first spatial segregation indices, but previous spatial indices were computationally intensive (Jakubs, 1981; Morgan, 1983), and there were no tools to implement them. Therefore, the primary goal of this project is to develop tools for researchers, practitionors, instructors, students, and policy planners to calculate these spatial indices. Because spatial information is necessary to compute these indices, therefore, Geographic Information Systems (GIS) technology has to be used. Details of the implementation process can be found in the papers listed below with "*".
A recent (January 2005) addition is to implement the
local segregation indices published in Wong (2002). The tools developed
is now incorporated into the same ArcView project file (.apr) - see the
Another goal of this project is to explore if
and spatial measures do give us different results. One aspect of the
differences is in terms of their
scale sensitivity. It has been demonstrated that using smaller areal
(such as census block groups as compared to census tracts) will usually
provide higher level of segregation (Wong, 1997; Wong et al., 1999). It
is not clear if spatial segregation will experienced more or less
with different scale level of the data are used. Results from this
are in Wong (2003, 2004).
Jakubs, J. F. 1981. “A Distance-Based Segregation Index.” Journal of Socio-economic Planning Sciences 15: 129-41.
Morgan, B. S. 1975. “The Segregation of Socioeconomic Groups in Urban Areas.” Urban Studies 12: 47-60.
Morgan, B. S. 1983. “An Alternative Approach to the Development of a Distance-Based Measure of Racial Segregation.” American Journal of Sociology 88: 1237-1249.
Morrill, R. L. 1991. “On the Measure of Geographical Segregation.” Geography Research Forum 11: 25-36.
Wong. D. W. S. 1993. “Spatial Indices of Segregation.” Urban Studies 30: 559-72.
Wong, D. W. S. 1996. "Enhancing Segregation Studies using GIS. Computers,Environment and Urban Systems, 20(2): 99-109.
Wong, D. W. S. 1997. “Spatial Dependency of Segregation Indices.” The Canadian Geographer 41(2): 128-136.
Wong, D. W. S. 1998. “Measuring Multiethnic Spatial Segregation.” Urban Geography 19: 77-87.
Wong, D. W. S. 1999a. “Geostatistics as Measures of Spatial Segregation.” Urban Geography 20(7): 635-47.
Wong, D.W.S., H. Lasus, and R. F. Falk. 1999. “Exploring the Variability of Segregation Index D with Scale and Zonal Systems: An Analysis of Thirty U.S. Cities.” Environment and Planning A 31: 507-22.
* Wong, D. W. 2001. “Desktop and
for Spatial Segregation Analysis”. Proceedings,
ESRI User Conference 2001.
(full version with figures from the author)
Wong, D. W. S. 2002. “Modeling Local Segregation: A Spatial Interaction Approach.” Geographical and Environmental Modelling, 6(1): 81-97.
* Wong, D. W. S. 2002. “Spatial Measures of Segregation and GIS.” Urban Geography 23(1): 85-92.
* Wong, D. W. S.
“Implementing Spatial Segregation
Measures in GIS.” Computers, Environment and Urban Systems 27:
Wong, D. W. S.
2003 "A Comparison
of Traditional and Spatial Measures of Segregastion: Some Empirical
Findings." In John W. Frazier and Florence Margai (eds) Multicultural Geographies: Persistence and
Change in U.S. Racial/Ethnic Patterns, Global Academic
Publishing, pp. 247-262.
Wong, D. W. S. 2004. “Comparing
Measures: A Spatial Scale Perspective.” Urban Geography 25(1): 66-82.