Download The Space-Filling Efficiency of Urban Form in Izmir

The Space-Filling Efficiency of Urban Form in Izmir:
A Historical Perspective Using GIS and Fractal
Dimension
April 29th – 30th, 2011
9th Meeting of AESOP
Thematic Group on “Complexity and Planning”
“Self-Organizing and Spatial Planning”
Istanbul, TURKEY
Gizem Erdoğan, McP
Department of City and Regional Planning
Pamukkale University
Denizli, Turkey
K. Mert Cubukcu, PhD
Department of City and Regional Planning
Dokuz Eylul University
Izmir, Turkey
Background
“Clouds are not spheres, mountains are not
cones, coastlines are not circles, and bark is
not smooth, nor does lightning travel in a
straight line.”
Mandelbrot (1983)
Background
First introduction of fractals by Mandelbrot
(1977) meaning:
“irregular and fragmented patterns around us,
(…) a new geometry of nature”
Background
Fractal Dimension (developed by Hausdorff,
1913 and Besicovitch): D, is a statistical
quantity that gives an indication of how
completely a fractal appears to fill space.
Background
Fractals are spatial objects whose geometric
characteristics include scale dependence,
irregularity, and self-similarity (Shen, 2002)
Background
Fractal dimensions of the built-up urban areas
is an efficient gateway for describing the
urban spatial system and the urban
morphology. Spatial fractal theory could be
used to analyze the urban physical form and
growth processes.
Literature
Recent research has demonstrated that the
urban form can not be fully described by
Euclidean geometry, but rather be treated as
fractals (Batty and Longley, 1987; Benguigui and Daoud, 1991;
Batty and Xie, 1996; 1999; Shen 1997; 2002).
Fractal dimension can avoid disadvantage of
scale.
Literature
The fractal dimension is expected to increase
as the city becomes increasingly dense,
using the space more efficiently (Ball, 2004).
Literature
The efficiency of urban form can well be measured
using fractal dimensions of the built-up urban
areas.
Fractal Dimension, D, is not a whole number and it is
usually between 1 and 2.
12
less efficient space filling  more efficient space filling
Literature
Batty and Longley, for example, shows that the fractal
dimension of London has increased from 1.32 to 1.79
between the years 1820 and 1962, indicating a better
form of spatial organization and more efficient spacefilling.
Lee (1989) analyzed the relationship between urban
population and built-up areas in the U.S. in 1960, 1970,
and 1980.
Çubukçu and Çubukçu (2009), analyzed space-filling
efficiency of Safranbolu, Turkey in time series in 1976
and 2007 as 1.712 and 1.80 respectively.
Aim
To examine the urban space-filling efficiency of
a Izmir Metropolitan Area,Turkey, using
fractal dimension for five different time
periods including 1951, 1963, 1987, 1996
and 2000 using GIS.
Data
Izmir is Turkey's third most populous city
with 3.370.866 (TUİK, 2010) with over 3,500
years of recorded urban history. and the
country's second-largest port city after
Istanbul.
İzmir has a typical urban growth pattern as an
example for Turkey urbanization history
where reconstruction was not common until
the 1950s.
Data
The data is collected for the İzmir Metropoliten
Area for the years 1951, 1963, 1996 and 2000.
The data used in the study were derived from the
digital and hardcopy aerial photographs and
satellite images available from the Municipality
of Izmir. Map of 1987 is from Landsat 5 (1,2,3),
map of 1996 from Landsat 7 (1,2,3).
Data
Data is:
 scaled
 georeferenced
 vectorized
 Re-rasterized
Using Photohop version 6, and then scaled, registered, and
vectorized using GIS software, ArcGIS 9.
Calculated using fractal analysis software, Fractalyse.
Data
Analysis
Following Batty and Longley (1994) and Shen (1997) and
Çubukçu and Çubukçu (2009), the box-counting method
is applied to estimate fractal dimensions for the five time
periods.
Box-counting method compute the number of cells cover
an object, with grid size and repeat the process changing
the box size to obtain a dataset. Regular grid over an
object and by counting the number of occupied cells.
Analysis
The estimated fractal dimension D is derived by
estimated slope of the log(n(s)) and log(1/s)
graph (Shen, 2002):
log(n(s)) = log(U) + Dlog(1/s) + εs
D : fractal dimension
log(U) : constant (U is builted area)
s : the box size
εs : the error term
Analysis
log(n(s))
D = slope
log(1/s)
Results
Results
Conclusion
The results are parallel to the claims in the literature.
The city of İzmir has moved from a less efficient spatial
organization and space-filling to a more efficient one
between the years 1960 and 2000.
The fall from 1,585 to 1,449 between 1951 and 1963 can
be explained by the first urban spill over as a result of
rural to urban migration in the 1950s.
Caveats


Data for the years 1951 and 2000 are
applied. More time periods (especially 1963
and 1996) should be considered.
Methods other than box counting should be
applied to generalize resutls.