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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B1. Istanbul 2004
system is easily seen by the blue tones, whereas the new
transversal east-west road stands out, contributing to the
enhanced connectivity within the wider metropolitan area.
As mentioned previously, the classification exercise for
determining the land cover classes for the 2003 images has, at
the time of writing, only been completed for one part of the
SPOT Scene, covering just 172 km? of the MAB. The full
results will be presented the ISPRS Conference in Istanbul in
July 2004, however it is worth mentioning that some nine land
cover classes have been isolated resulting from the supervised
classification methodology used and described under Section
2.3 of this paper: shadow; 3 industrial classes; residential; soil;
green; shallow water; and occupied area.
Figure 6 illustrates a detail of the final map resulting from the
aforementioned. supervised classification process, focusing on
the industrial areas of the Zona Franca, in Barcelona, lying to
the north of the Llobregat River and the adjoining Logistic
activities zone (ZAL), within the municipality of El Prat de
Llobregat, lying to the south.
X
Figure 6: Example of the resulting supervised classification
© SPOT Image Copyright 2003, CNES
4. DISCUSSION AND CONCLUSIONS
4.1 Monitoring urban sprawl
Official figures relating to the growth in population of the
Metropolitan Area of Barcelona for the five-year period 1996-
2001 indicate an overall increase in population of some
0.295%. This demographic change has by no means been
uniform, as is highlighted by Table 3. While the population of
the City of Barcelona has decreased by some 0.326%, the
remainder of the Metropolitan Area under the jurisdiction of the
MMAMB saw an overall increase in population of just over
1%.
This level of growth is more modest than that suggested by
Table 2, but is probably nearer the truth for a number of
reasons. On the one hand the spatial extent of the MAB is just
one part of the much wider territory subjected to the satellite
image interpretation (remote sensing) comparison between 1995
and 2003. On the other hand this comparison identified just
three very broad classes of land cover: occupied areas (implying
some form of human intervention), green areas and soil.
Furthermore the two images used for this comparative exercise
are in raster data format. For greater accuracy they would need
to be in vector data format enabling the delimitation of
polygons and the determination of exact areas. Once this
conversion procedure has been carried out upon the SPOT
Images used in this project, the research team will then be in a
position to quantify with precision the level of urban growth
and development experienced between 1995 and 2003 within
the limits of the MAB, and make the judgement as to what
extent this growth can be constituted as urban sprawl.
1996 2001 % change
Barcelona 1,508,805 1,503,884 -0.326
Rest of MAB 1,328,735 1,342,041 +1.001
Total MAB 2,837,540 2,845,925 0.295
Table 3: Change in population for the Metropolitan Area of
Barcelona 1995-2003
As yet, the research project referred to here is not sufficiently
advanced to offer conclusive results concerning the
quantification and qualification of urban sprawl or urban
growth within and on the edge of Barcelona’s metropolitan
area. However the emerging results clearly corroborate the
hypothesis of increased land consumption beyond the central
core of the MAB.
In this sense the morphological approximation to the
delimitation of urban and/or metropolitan systems through the
interpretation and analysis of satellite images, particularly
incorporating a dynamic approach by comparing two points in
time, would appear to offer a clear advantage over more
functional approaches. By simply superimposing the carlier and
later of two images, as carried out in Section 3.1 and illustrated
by Figures 4 and 5, the professionals working in the realm of
urban and regional planning are provided with a wealth of
information. This enables them to determine at a glance the
arcas where development pressures have been most strongly
experienced.
4.2 Conclusions
Part of the reasoning behind the invitation extended to the
UPC/MMAMB from the CNES and SPOT Image to participate
in the SAVP exercise was to gain feedback on the potential
applications of Spot 5 data for the purposes of urban planning.
With this in mind, although the final results of the project are
still to be reached, it seems appropriate to offer some comments
concerning the enhanced characteristics of the Spot 5 Images,
resulting from the increased resolution.
The difference between the 2003 and the 1995 images, in terms
of increased visual clarity and quality, is patently obvious from
Figure 7. This illustrates the built-up fabric of Barcelona,
incorporating the city’s historic core to the north-east adjoining
the former Port Area, today with a leisure boat marina and other
recreational/leisure uses, and the grid-ironed 19" Century
extension to the city to the north-west. The clarity of the urban
fabric in the southern portion of the figure contrasts sharply
with the more blurred nature of the northern section.
Figure 7 clearly provides very real and local evidence of the
potential for a deeper understanding of the dynamics of urban