Image Processing Reference
In-Depth Information
14.1
Introduction
Nearly half of the world's human population is now believed to live in urban areas
(United Nations
2001
). The rate of global population growth is currently decreasing
but demographic momentum implies that population growth will continue until at
least the year 2100 (O'Neill et al.
2001
). Almost all of this population growth is
expected to occur in urban areas (United Nations
2001
). Widespread urbanization
also tends to concentrate this growing population into dense settlements at rates
often exceeding 3% per year. Contrary to popular belief, short-term (<50 years)
population growth is expected to occur not in megacities (>10 million inhabitants)
but rather in moderate sized urban areas of developing countries maintaining high
birth rates (United Nations
2001
). Furthermore, most of this growth is expected to
occur in developing countries where economic conditions may not provide the
resources necessary to maintain the integrity of the physical environment.
Urban sprawl and associated large-scale alteration of the natural landscape
(Chapter 2) will continue to escalate and have a profound effect on environmental
conditions and processes. In addition to challenges pre-
sented in the area of land use planning, housing, pollution
and development, urbanization has received much of
attention worldwide due to implications for changes in
microclimate, regional scale climates, and impact of
potential sea level rises. There is much ongoing and future
research of this phenomenon as a major component of
anthropogenic climatic changes. The understanding of
relations among urban systems, microclimate, and global
scale climates has lead to the creation of several interest
groups and much information continues to appear in the
literature and on the internet; however coherent syntheses
are relatively rare. A major objective of city planners is to
ensure a healthy and pleasant environment for inhabitants and avoid any harmful
repercussion from any large-scale changes. Any effective mitigation techniques
should be based on an effective long-term environmental monitoring because of the
constant change of urban morphology and environmental conditions.
Remote sensing provides an invaluable tool for the long-term monitoring of
urban growth and surface conditions. The synoptic view of urban land cover pro-
vided by satellite-based sensors is an important complement to in situ measure-
ments of physical and environmental conditions in urban settings. Other advantages
of remote sensing applications include the combination of cost-effectiveness, non-
destructiveness and relative high spatial resolution, repetitive data at the same scale
for a particular satellite, digital format, and acquisition of imagery from inaccessi-
ble areas without the hindrance of political or security restrictions. Forster (
1983
)
provides a thorough summary of the early evolution of urban remote sensing and
introduces a methodology with which some socioeconomic parameters may be
predicted using reflectance based estimates of land cover classes. Compared to
the environmental
implications of
urbanization
include effects on
microclimate,
regional scale
climates, and
impact of
potential sea
level rises
