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--- wiki:remote_sensing [2017/03/21 11:31] – claudemeisch
+++ wiki:remote_sensing [2017/08/17 15:10] (current) – apolderman
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 Jensen (2007) defines remote sensing as:
-//„the non-contact recording of information from the ultraviolet, visible, infrared, and microwave regions of the electromagnetic spectrum by means of instruments such as cameras, scanners, lasers, linear arrays, and/or area arrays on platforms such as aircraft or spacecraft, and the analysis of acquired information by means of visual and digital image processing“.//
+>//„the non-contact recording of information from the ultraviolet, visible, infrared, and microwave regions of the electromagnetic spectrum by means of instruments such as cameras, scanners, lasers, linear arrays, and/or area arrays on platforms such as aircraft or spacecraft, and the analysis of acquired information by means of visual and digital image processing“.//
 The results of remote sensing are images with an abundance of information allowing us to //“determine the composition and nature of the Earth’s surface and atmosphere from local to global scales”// (Kitchin & Thrift, 2008). Through the repetitive nature of the remote sensing, these images hold information about changes at different points in time and are thus good proxys for [[:wiki:ecosystemservices?s[]=ecosystem&s[]=services|ecosystem services]], see [[:wiki:indicators?s[]=indicator|indicators]]. Thus remote sensing is a powerful tool to assess information that would otherwise be difficult to obtain within the same scale of time and space. Consequently, remote sensing becomes //“a multi-faceted, multi-disciplinary endeavour to acquire information from targets”// (Clark & Rilee, 2010).
+==== Basic Principles ====
 The foundation of remote sensing lies within the measurement of reflected and emitted electromagnetic radiation from the Earth’s surface and this radiation is measured and categorized as a function of its wavelength on a logarithmic scale (Jorgensen & Fath, 2008). Remote sensing uses the physical principle of radiation to determine characteristics of surface depending on the emitted or reflected wavelength (Kitchin & Thrift, 2008). These wavelengths are in the following categories: Ultraviolet, Visible, meaning visible to the human eye (VIR). In near-Infrared (NIR), where reflected radiance is measured. In the mid-infrared, where reflected and emitted radiance can be measured and in the far-infrared, where only emitted energy is measured in the form of thermal energy, here referred to as TIR (Clark & Rilee, 2010). The advantage of multispectral remote sensing is related to the different types of materials which can be distinguished on the basis of differences in their spectral signatures (Schowengerdt, 2007). The remote sensors are categorized into active and passive sensors. Active sensors generate their own signal which is sent to the Earth’s surface and the reflection is measured, e.g. RADAR or LIDAR. Passive sensors measure emittance and reflection from the Earth’s surface of solar energy (Kitchin & Thrift, 2008).
 ==== Basic components ====
+{{  :wiki:clark_rs.png?500  }}
+<font 9px/inherit;;inherit;;inherit>A typical remote-sensing system. Components and Energy Pathways (from Clark & Rilee, 2010)</font>
 The basic components of a remote sensing systems are
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   * an energy sink (Earth’s surface objects)
   * and a sensor platform capturing the reflected and emitted radiance onto a recording medium (Schowengerdt, 2007).
-{{ :wiki:clark_rs.png?300 |}}
 With respect to analog arial photography where a lens is focusing the light on photographic film, digital sensors record photons for a specific range of wavelength (Kitchin & Thrift, 2008), and these are stored as digital numbers representing brightness values as an array of pixels.
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 ----
-Jensen, J. R. (2007). Remote sensing of the environment: An earth resource perspective (2nd ed). Prentice Hall series in geographic information science. Upper Saddle River, NJ: Pearson Prentice Hall.
+Clark, P. E., & Rilee, M. L. (2010). Remote sensing tools for exploration: Observing and interpreting the electromagnetic spectrum. New York: Springer.
 Kitchin, R., & Thrift, N. J. (2008). International encyclopedia of human geography. Amsterdam: Elsevier.
+Jensen, J. R. (2007). Remote sensing of the environment: An earth resource perspective (2nd ed). Prentice Hall series in geographic information science. Upper Saddle River, NJ: Pearson Prentice Hall.
 Jorgensen, S. E., & Fath, B. (2008). Encyclopedia of Ecology, Five-Volume Set. Oxford: Elsevier Science.
-Clark, P. E., & Rilee, M. L. (2010). Remote sensing tools for exploration: Observing and interpreting the electromagnetic spectrum. New York: Springer.
+Schowengerdt, R. A. (2007). Remote sensing: Models and methods for image processing (3rd ed). Burlington, MA: Academic Press.
-Schowengerdt, R. A. (2007). Remote sensing: Models and methods for image processing (3rd ed). Burlington, MA: Academic Press.
+~~DISCUSSION~~
+{{tag> "ecosystem_services" "AlpES_project" }}