Environmental Engineering Reference
In-Depth Information
2.1 Introduction
and global urban land use/cover has been the subject of numer-
ous studies and evaluations since the early 1970s (e.g., Gaydos
and Newland, 1978; Jensen, 1981; Haack, Bryant and Adams,
1987; Kwarteng and Chavez, 1998; Yang and Lo, 2002; Auch,
Taylor and Acededo, 2004; Seto and Fragkias, 2005; Small, 2005;
Schneider and Woodcock, 2008), which was largely stimulated by
the launch of ERTS-1 (Earth Resources Technology Satellite-1;
later renamed as Landsat) in 1972. Images acquired by the US
Landsat program and French SPOT satellites are the principal
sources of data. Additionally, large volumes of valuable data have
been acquired by the Indian remote sensing satellites (IRS), the
NASA Terra satellite, the China - Brazil Earth resources satel-
lites (CBERS), and several European, Canadian, and Japanese
satellites carrying active imaging devices.
This chapter will focus on the use of the data acquired by
the Landsat program that provides the longest continuous obser-
vations of Earth's surface from space. The Landsat system is
the only satellite system designed and operated to repetitively
observe Earth's landmass at moderate resolution. It offers a
rich archive of highly calibrated, multispectral data of global
coverage that recently becomes available at no charge from the
USGS EROS Data Center. The Landsat data set has been an
invaluable resource for examining natural and anthropogenic
changes on Earth's surface. This chapter will specifically discuss
the utilities of archival Landsat data for the observation and
measurement of urban spatial growth and landscape changes.
It comprises three major components. First, we provide an
overview of the past, present and future of the Landsat program
and its imaging sensors, which will be tied with various invento-
rying and mapping activities in the urban environment. Second,
we present a case study focusing on a rapidly suburbanizing
American metropolis to demonstrate the usefulness of time-
sequential Landsat imagery for monitoring urban growth and
landscape changes over nearly the past four decades. Last, based
on this case study and other literature, we further identify a com-
mon workflow for urban growth monitoring, and discuss some
conceptual and technical issues emerging when using archival
satellite images acquired by different sensors and perhaps during
different seasons.
Over the past several decades, humans have substantially altered
Earth's surface, predominately through agriculture, deforesta-
tion, and urbanization (Kondratyev, Krapivin and Phillips, 2002;
Foley et al ., 2005; Turner, Lambin and Reenberg, 2007). Rates of
deforestation and the dedication of marginal lands to high-impact
agriculture have varied widely across the world, but there has
been a consistent world-wide increase in the number of people
residing in cities (Kaplan, Wheeler and Holloway, 2009). In 1950,
only one-third of the world's 2.5 billion were urban dwellers. In
2010, more than half of the 6.9 billion people of our planet live
in cities. At the global scale, the growth of urban areas shows
no signs of slowing down and likely continues unabated into
the next several decades (UN-HABITAT, 2010). Urban growth
has frequently been viewed as a sign of the vitality of a regional
economy, but it has rarely been well planned, thus provoking
concerns over the degradation of our environment and ecological
health (Lo and Quattrochi, 2003; Carlson, 2004; Grimm et al .,
2008). Monitoring urban growth and landscape change is critical
both to those who study urban dynamics and those who must
manage resources and provide services in the urban environment
(Yang, 2002, 2007, 2010; Alberti, Weeks and Coe, 2004; Auch,
Taylor and Acededo, 2004).
Assessment of urban growth and landscape change involves
the procedures of inventorying and mapping that require a
reliable information base and robust techniques (Yang, 2003).
Urban and landscape patterns are observable and therefore can
be mapped through ground surveys or remote sensing. While
ground surveys are often limited by logistical constraints and
largely localized by nature, remote sensing makes direct observa-
tions across large areas of the land surface, thus allowing urban
and landscape patterns to be mapped in a timely and cost-
effective mode (Lindgren, 1985; Lo, 1986; Jensen and Cowen,
1999; Mittelbach and Schneider, 2005). Using archival remote
sensor data, a spatio-temporal assessment of urban growth and
landscape changes can be obtained (e.g., Yang, 2002; Herold,
Goldstein and Clarke, 2003; Seto and Fragkias, 2005; Bhatta,
2010). Evaluation of both static and dynamic attributes of land
surface extracted from remote sensor data may allow the types of
changes to be characterized and the proximate sources of change
to be identified or inferred (Lo and Yang, 2002). Such informa-
tion is useful for the evaluation of interactions among the various
driving forces that can further help develop computer-based
models to predict future urban growth and landscape changes
(Kline, Moses and Alig, 2001; Yang and Lo, 2003).
Over the past several decades, data from various remote sen-
sors have been used to map urban growth and landscape changes.
Before the advent of satellite remote sensing, aerial photography
played a key role in producing urban land use/cover maps, and
remained critical for such a purpose (e.g., Lindgren, 1985; LaGro
and DeGloria, 1992) until the late 1990s when high-resolution
satellite imagery became available (e.g., Herold, Goldstein and
Clarke, 2003; Ellis et al ., 2006). The high-resolution remote
sensor data allow a substantial proportion of the basic land
use/cover units to be distinguished, yet they are constrained by
the high cost of data acquisition and the technical difficulties
in data processing when the study area under investigation is
quite large. The acquisition of information on regional, national
2.2 Landsat programand
imaging sensors
The Landsat (originally Earth Resources Technology Satellite-
ERTS) program was initiated in 1966, which was largely inspired
by the success of the early meteorological satellites and the orbital
photography of the Earth's surface taken during the manned
spacecraft missions in early 1960s. The program has resulted
in the successful launch of six land satellites, with the first
one on 23 July 1972, signaling a new age of terrestrial remote
sensing from space. The first three satellites were launched with
the Return Bean Vidicon (RBV) and the Multispectral Scanner
(MSS) onboard, the fourth and fifth include the MSS and the
Thematic Mapper (TM), the sixth with the Enhanced Thematic
Mapper (ETM) onboard failed upon launch, and the seventh
carries the Enhanced Thematic Mapper Plus (ETM + ). These
Landsat sensors were designed with moderate resolution that is
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