The Spatial GINI Coefficient
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Transcript of The Spatial GINI Coefficient
The Spatial GINI Coefficient
Dr. Paul C. SuttonDepartment of Geography
University of DenverPopulation Assocation of America Conference
San Francisco May 3rd, 2012
Outline• Lorenz Curve and the GINI Coefficient
as a measure of distribution of wealth
• Global gridded representations of Nighttime Satellite Imagery and Population Density as an alternative source for developing a spatially derived Lorenz Curve.
• The Human Development Index (HDI)
Data Products Used
Nighttime Lights of the WorldDMSP OLS (NGDC)
LandScan Global Grid of Population
Scatterplots of Light vs Population for Pixels in China (left) and U.S. (right)
The Spatial GINI Coefficient I10 km x 10 km
Population Grid10 km x 10 km
DMSP OLS Image0 0 0 0 0 0 0 0 0 0
0 0 1 1 2 1 2 1 4 1
1 1 3 2 3 4 4 4 3 1
1 1 4 5 5 5 10 5 5 2
1 2 5 5 10 10 10 10 10 3
1 3 5 5 10 30 50 30 10 4
2 2 5 10 10 50 100 50 10 10
15 5 5 5 10 30 50 30 10 3
4 3 5 5 10 10 10 10 10 2
0 2 5 5 5 5 10 5 5 1
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 2 0 0 0
0 0 0 0 2 2 10 1 2 0
0 0 0 0 2 50 150 50 5 0
0 0 0 0 10 150 255 150 10 2
5 0 0 0 2 50 150 50 5 0
0 0 0 0 0 5 10 5 2 0
0 0 0 0 0 0 0 0 0 0
Analysis of the population grid relative to the light grid (above)produces a table that contrasts % of Population to % of light in
any given country or area (See table below).
Light Level (DN) Pop in DN Cum % of Light Cum % of Pop0 205 0.0 25.01 10 0.1 26.22 90 1.5 37.25 55 3.7 43.910 40 7.2 48.850 120 24.8 63.4150 200 77.6 87.8255 100 100.0 100.0
Total Pop = 820 Total Light = 1137
The Spatial GINI Coefficient II(also referred to as the “Lumen GINI”)
Spatial Lorenz Curve
0
20
40
60
80
100
0 20 40 60 80 100
Cumulative % of Population
Cu
mu
lati
ve %
of
Lig
ht
Pink Area
Yellow Area
The“Lumen GINI”
Coefficient
A ‘lumen GINI’ of 1.0implies one person liveswhere all the light is and
everyone else is in the dark.A ‘lumen GINI’ value of 0.0implies light is distributed
equally amongst all people.
63.8 % of Popwith 24.8%
of Light
The “Real” Income GINI Coefficient
Note: Research suggests the United States is on track to pass Mexico
Highly variable ‘freshness’ of Data
Due to the lack of a systematic international data collection system, the data used to calculate income Gini coefficients span nearly two decades
The Global Spatial GINI
The Lorenz curve for the global Lumen Gini Coefficient, formed by combining the data from all countries.
Lorenz curves and Lumen Gini coefficients for six countries
GINI = 0.941 GINI = 0.748 GINI = 0.981
GINI = 0.791 GINI = 0.623 GINI = 0.542
Map of national Spatial GINI Coefficients
Map of Subnational Spatial GINICoefficients
Map of Spatial GINI Coefficientsat a 0.25 degree grid
Spatial GINI vs. Income GINI
National level Lumen Gini versus Income Gini coefficients. Note the poor correlation, indicating that the two Gini’s are measuring very different phenomena.
Spatial GINI vs Per Capita Energy Consumption and
Electrification Rates
Spatial GINI vs. Human Development Index
Spatial GINI vs. Human Security Index
Spatial GINI vs. Ecological Footprint
Discussion & ConclusionsThe Spatial GINI or Lumen GINI does not measuredistribution of wealth in any manner similar to the Income GINI.
The Spatial GINI correlates strongly and significantlywith both the Human Development Index (HDI) andThe Human Security Index (HSI).
Simple, empirical measures such as the Spatial GINIas presented here present an opportunity for improvedspatially explicit characterizations of the human condition.