Some
definitions of remote sensing.
1. Here are some definitions about remote
sensing.
a.
Remote sensing is the science of acquiring, processing and
interpreting images that record the interaction between electromagnetic energy
and matter. (Kerle (2004) after
Sabins (1996).
b.
Remote sensing is the instrumentation, techniques and
methods to observe the Earth's surface at a distance and to interpret the
images or numerical values obtained in order to acquire meaningful information
of particular objects on Earth. (Kerle
(2004) after Buiten (1993).
c.
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. (Lillesand & Kieffer, 2004).
d.
Remote sensing is the science (and to some extent, art) of
acquiring information about the Earth's surface without actually being in contact
with it. This is done by sensing and recording reflected or emitted energy and
processing, analyzing, and applying that information. (CCRS).
e.
Remote sensing is the use of
environmental sensors placed in orbit around the earth to observe climate, vegetation
and rainfall dynamics, enabling a daily global assessment of ecosystem health.
These observations have formed the foundation of famine early warning systems
by providing quantitative assessments of food production across large areas.
Although this information is a critical piece of famine early warning, food
security is rarely ensured by adequate food production alone (Molli E. Brown,
2008)
f. Remote Sensing idescribe the collection of data about an
object, area, or phenome non from a distance with a device that is not in
contact with the object. More commonly the term remote sensing refers to
imagery and image information derived by both air borne and satellite platforms
that house sensor equipment. The data collected by the sensors are in the form of
electromagnetic energy (EM). Electromagnetic energy is synonymous to many
terms, incluiding electromagnetic radiation, radiant energy, energy, and
radiation (Departement Of The Army. US Army Corps of Engineers).
g. Remote sensing is the science and
art acquiring information by a recording device that is not in physical contact
with the object under investigation (Xiaojun Yang, 2009).
Regarding
to those definitions, according to my opinion the best definition especially
for the field of interest of watershed and coastal management would be the 4th
one:
“Remote
sensing is the science (and to some extent, art) of acquiring information about
the Earth's surface without actually being in contact with it. This is done by
sensing and recording reflected or emitted energy and processing, analyzing,
and applying that information. (CCRS)”
This
definition is more complete compared to others. For example is the 1st
definition, it doesn't include the object matter, Earth. The 2nd and
the 3rd definition tend to be incomprehensive as the utilisation of
remote sensing data is rather subtle. On the other hand, This definition (the 4th)
includes the object matter, Earth's surface. Furthermore, coastal and watershed
management tend to be an applied work. while the definition (the 6th)
Department Of The Army . U.S. Army Corps of Engineers ) more to the technique
of remote sensing and this definition (the 7th) generally without
explaining its study object.
So
that in relation to coastal and watershed management processing, analyzing, and
applying are important. Other things instead of processing, analyzing, and
applying information from remote sensing would be less important, but needed.
Indeed, it means that we don't omit completely about basic concepts of remote
sensing relating to the process of data acquisition stated in the definition
above. Processing, analyzing, and applying information obtained from remote
sensing data is not an arbitrary decision, these three subjects are important
since those are “real things” of remote sensing, and all at one answering the
question “what's remote sensing for?”. Then again, it needs a good decision
before processing, analyzing, and applying the information.
Processing,
analyzing, and applying remote sensing data we have to know the characteristics
of the data. An understanding in data characteristics would help how to
process, analyze, and apply remote sensing data suite to the objective of the
study, in this case related to watershed and coastal management. Characteristics
data help to decide what should the users do so that data which are supposely
to use is suitable for the study matter. For instance, studying watersheds, we
need landuse data, then we should decide mapping scale so that suits
availability of the data. In the meantime we should choose data that possibly
to use for deriving landuse information from remote sensing data. What's more,
understanding characteristics of remote sensing data is important as it
influences in deciding how to process, analyze, and apply. Remembering that
type of work in watershed and coastal management is an applied work, it can be
concluded that 4th definition proposed by CCRS is the best one since
it encompasses
many things including “steps” of acquisition until application.
2. The advantages of remote sensing for national
watershed and coastal study.
Indonesia
encompasses from Sabang until Merauke which is vast area shared into 17,508
islands with almost 2 millions square metres. It supposes to need a high demand
of maintenance related to its territory. One of maintenance of territory is
managing watersheds and coastal areas.
Regarding to the vast area of
Indonesia, it needs tools that can accommodate its need, in this case is
managing watersheds and coastal areas. Remote sensing could be the best tool
for managing watersheds and coastal areas. As defined above, the work or
managing watersheds and coastal areas would be easier than relying only on
terrestial data. Remote sensing provides multitemporal data and multiresolution
data and basically, it also provides various data (with its own charactere)
which are needed for managing watersheds and coastal areas. Regarding to this
synaptic charactere, it would be easier to extract designated features needed.
Talking about time, remote sensing is time-saving in regards to field work and
it also has repetive character, which is possible to monitor a certain feature
temporaly. Moreover, remote sensing helps to discover remote area, in case of
accessibility, as many unaccessesable areas in Indonesia. This hugely help in
development and monitoring. Furthermore, remote sensing tends to be
cost-efficent than terrestial survey.
Those advantages as stated above can
be described below as an application from this following example. Savant et.al
(2002) in their publication showed the applications of remote sensing for
waterhed delineation. Watershed management in this publication is using
remotely-sensed data for delineating watershed such as river flows and their
tributaries and also watershed boundaries. Study area in the research is Upper
Pearl watershed in Mississippi. The research uses DEM data obtained from USGS
with a standar USGS DEM of 1: 25,000 scale correspondng to a cell size of
thirty meters by thirty meters. Process of delineating the remotely-sensed data
using ArcView and HEC-HMS. Proceesed data compared to a USGS fiel survey of
provided data. The comparison showed that the result is good enough though
there are some limitations. The thing is that using remotely-sensed data took
only couple of days compared to conventional method that took over a month.
This research successfully demostrated that the used of remotely-sensed data
and commercially available software is an effective approach to developing
accurate watershed analysis for various usages with a minimum amount of time, effort,
and cost.
Departement Of The Army. 2003. Enginering and Desaign Remote Sensing. US Army Corps of Engineers
CCRS (Canada Centre of Remote Sensing). Fundamentals of Remote Sensing. Canada.
Kerle, N., Janssen, L.L.F., Huurneman, G.C., Bakker, W.H.,
Grabmaier, K.A., Van dee Mer, F.D. (2004) . Principle
of Remote Sensing (ITC Educational Textbook Series). Enschede : The
International Institute for Geo-Information Science and Earth Observation.
Lillesand, T.M., & Kieffer, K.W.
(2004) . Remote Sensing and Image
Interpretation. New York: John Wiley & Son Inc.
Molli E. Brown. 2008. Famine
Early Warning Systems and Remote Sensing Data. Springer-Verlag Berlin
Heidelberg.
Savant, Gourav., Lei Wang., Dr.
Dennis Truax. 2002. Remote Sensing and
Geospatial Applications for Watershed Delineation. Proceeding XXXIV International Society for Photogrammetry and Remote Sensing
(ISPRS)
Xiaojun Yang. 2009. Remote
Sensing and Geospatial Technologies for Coasstal Ecosystem Assessment and
Management. Springer-Verlag
Berlin Heidelberg
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