Geography Reference
In-Depth Information
Chapter 2
Theoretical Background and State
of the Art
This chapter provides a short overview of the principles of remote sensing outlines
current studies focused on the Euphrates River Basin (ERB) and presents a survey
of the literature available on the topics that the thesis covers. Within the confines
of this study, remote sensing is defined as the measurement of emitted or reflected
electromagnetic radiation, or spectral behaviors, from a target object by a multi-
spectral satellite sensor. This thesis contains four main sections: land use/land
cover classification, the mapping of irrigated areas, irrigated agriculture mapping
(especially crops classification), and land use/land cover change detection map-
ping. A great number of papers have been published on the above four topics. In
this section a small range is given, based on significance and likeness to this thesis,
with the goal of providing no wide-ranging survey, but of giving an experience of
the techniques, applications and performances found in the literature.
2.1 Remote Sensing Concept
For purposes of this text, discussion has been limited to Earth observation from
space. ''Remote sensing is the science and art of obtaining information about an
object, area or phenomenon through the analysis of data acquired by a device that
is not in contact with the object, area or phenomenon under investigation. Using
various sensors, we remotely collect data that may be analyzed to obtain infor-
mation about the objects, areas or phenomena being investigated. The remotely
collected data can be of many forms, including variations in force distributions, or
electromagnetic energy distributions'' (Lillesand et al. 2008 ). Figure 2.1 illustrates
the generalized processes and elements involved in the electromagnetic remote
sensing of Earth resources.
Key to the consideration of remotely sensed imagery is the coverage, resolution
and density of its spectral, spatial and temporal characteristics. Spectral coverage
describes which part of the EMS (Fig. 2.2 ) is being used (e.g., visible, infra-red,
thermal, etc.). Spectral resolution indicates to the spectral bandwidths in which the
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