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3.1 Sprawl and Landscape Indicators
The results obtained allow studying comparatively, in addition
to the degree of land consumption, the morphology of the
urbanization of the world’s megacities. The subdivision of the
windows of 45,000 sq. km in a grid composed of cells of one
sq. km, enables the construction of various landscape indicators,
such as the artificialized Index (the percentage of total area
occupied by urbanized land), the fractal dimension, the
dominance index, the entropy or the MECI of each cell. These
indicators allow us to understand the similarities and differences
between landscapes of different mega-cities, and then
characterize the typology of urban sprawl process.
Mexico
hr ai 9
London
REUS Im
Shanghai
Figure 6.The Urban Entropy
The spatial distribution of the entropy of the patches of
artificialized land in the areas studied shows how there is a
greater fragmentation of urbanization in the metropolitan
periphery (red color in the images, see figure 6)while in urban
centers, subcenters and rural areas (green in images) the entropy
or complexity is lower.
The explanatory models of the spatial distribution of entropy
show a clear quadratic structure, maximum at the intermediate
distances that characterize significant urban sprawl processes.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
F? Cuadrático «0.791
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Figure 7.Spatial Distribution of the Urban Entropy of the
Artificialized Land of Chicago according to the distance to
CBD.
84
4. CONCLUSIONS
Monitoring urban sprawl using remote sensing is fundamental
to understand the contemporary process of urbanization on a
global scale. As a result of this research, among others, our
center of research on Land Policy and Valuations is developing
a platform called GLOBUS to observe the global urban sprawl
(http://www-cpsv.upc.es/GLOBUS), and its purpose is to
continue studying and analyzing the process of urban sprawl in
a representative sample of most populated metropolitan areas,
intermediate cities and singular small cities with the hypothesis
that the process of urban sprawl is a phenomenon which is not
limited to the developed world and it is a global scale process.
The urban trend to sprawl brings negative effects on
sustainability and social inclusion. The Global Observatory
should be an extra tool to make decisions on urban plans and
policies for our cities in the XXI century.
Finally, the paper present here demonstrates how useful are the
methodology developed for monitoring the sprawl, starting from
using Landsat 7 imagery with low resolution for doing the per-
pixel classification and texture analysis. Also the methodology
represents a fast and suitable system to detect and measure
accurately the artificialized land of the mega-cities as proves
the accuracy index greater than 90% in all the studied
metropolises.
5. BIBLIOGRAPHY
Alhaddad, B, Burns, M & Roca, J, 2007. Texture Analysis for
Correcting and Detecting Classification Structures in Urban
Land Uses. Metropolitan Area Case Study — Spain. Urban
Remote Sensing Event. Paris, 2007.
Alhaddad, B., Roca, J., Burns, M., 2009. Monitoring urban
sprawl from historical aerial photographs and satellite imagery
using texture analysis and mathematical morphology
approaches. 49th European Congress of the Regional Science
Association International - 25th to 29th of August 2009 - Lodz,
Poland". 2009, p. 1-9.
Atkinson, P.E. & Tate, N.J., 1999. Techniques for the Analysis
of Spatial Data. In Advances in Remote Sensing and GIS
Analysis, Atkinson, P.E. and N.J. Tate (Eds.). John Wiley and
Sons, Chichester, pp: 1-7.62 Campbell.
