Image Processing Reference
In-Depth Information
most urbanized country, whereby the proportion of people living in urban areas
climbed from 44% (19.6 million in 1980) to 74% (47.7 million in 1999). The ran-
dom and rapid urbanization in Turkey during the past two decades has caused
pressing problems such as higher death tolls in earthquakes and inadequate educa-
tion and health services (WBG
2000
).
Formal settlements “refer to land zoned residential in city master plans or occu-
pied by formal housing” (UN-HSP
2002
). In contrast, informal settlements are
defined as: “(i) residential areas where a group of housing
units has been constructed on land to which the occupants
have no legal claim, or which they occupy illegally, and (ii)
unplanned areas where housing is not in compliance with
current planning and building regulations” (UN-HSP
2002
).
Informal settlements in developing countries are typically
located on the fringes of cities and characterized by a “dense
proliferation of small, make-shift shelters built from diverse
materials, degradation of the local ecosystem and by severe
social problems” (Mazur and Qangule
1995
).
According to a report of the UN Human Settlements
Programme on human settlements (UN-HSP
2002
), 30-60%
of urban residents in developing countries live in informal
settlements. However, accurate population estimates and
maps of these areas are scarce or nonexistent, making it dif-
ficult for authorities to enhance the situations of these areas.
Aerial photography, satellite data or land use maps can be used to evaluate the area
occupied by informal settlements. This is typically complemented by mapping appli-
cations incorporated into Geographical Information Systems (GIS) and global posi-
tioning systems (GPS), which are increasingly used to provide ground truth data.
informal
settlements
represent illegal
or unplanned
residential areas
not in
compliance with
regulations, and
are typically
characterized by
a complex mix
of social and
environmental
problems
Assessing Urban Land Use Change in Developing Countries
Over the years, aerial photography has been successfully utilized for mapping,
monitoring, planning and development of urban sprawl, urban land use and
urban environment. For reasons of their widespread availability, stereo
and revisit capability, frequency of update and cost, reliable and accurate
data, however, the focus of urban remote sensing research has shifted more
towards the use of digital satellite images such as IKONOS, QUICKBIRD,
EROS, LANDSAT, SPOT etc. (Donnay et al.
2001
). As discussed in earlier
chapters, some characteristics of the satellite sensors, for example spatial
and spectral resolutions, influence their applications for mapping change in
urban areas.
For example, crop and harvest forecasts are especially useful in developing
countries. LANDSAT data can be used very successfully in identifying crop
