Emote sensing and geographic information systems c Essay

This essay has a total of 926 words and 4 pages.

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emote sensing and geographic information systems can be defined as follows: "Remote
sensing is any method of obtaining and recording information from a distance. The most
common sensor is the camera; cameras are used in aircraft, satellites, and space probes to
collect information and transmit it back to Earth (often by radio). The resulting
photographs provide a variety of information, including archeological evidence and weather
data. The images are also used in map-making. Microwave sensors use radar signals that
penetrate cloud. Infrared sensors measure temperature differences over an area. Computers
process data from sensors." ("remote sensing" World Encyclopedia. Philip's, 2005. Oxford
Reference Online. Oxford University Press. Charles Darwin University. 12 September 2005 ).
"Geographic (Geographical) Information Systems (GIS), GIS are integrated, spatial,
data-handling programmes which will collect, store, and retrieve spatial data from the
real world. They are powerful tools in decision-making, as they can incorporate
co-ordinated data. It should be noted, however, that GIS only contain selected data;
solely the properties which investigators have considered relevant, so that many variables
will not be fed into the systems." "Geographic (Geographical) Information Systems" A
Dictionary of Geography. Susan Mayhew. (Oxford University Press, 2004. Oxford Reference
Online. Oxford University Press. Charles Darwin University. 12 September 2005 ) The
relationship between remote sensing and GIS is that remotely sensed data is one of the
input datasets in GIS. GIS can have other input datasets such as population data, species
data, climate data etc. "GIS has the ability to analyse these input datasets in a spatial
context and produce a conclusion which the operator of the system can interpret and use to
help develop a solution to the problem being investigated."
(http://erg.usgs.gov/isb/pubs/gis_poster)


The differences in remote sensing and GIS can be discovered in the data storage format and
information processing focus of the data. Remote sensing will first be discussed first.
The data collected in remote sensing is in the form of a raster image. The data in the
images are implicit in georeferencing. This means that the spatial addresses of individual
elements are determined by the ordering of the element in the data structure. The data
does not have an inherent topology. This is where the grouping of elements into structural
units is not inherently done. The data structure is simplistic - regular Cartesian grid.
GIS data on the other hand is often, but not always, stored in vector format. The data
collected in GIS is explicit georeferencing. This means that the spatial position of
elements is a make up of part of the definition. The topology of the data is specified
with each element. The data structures are more complex than raster format data. Remote
sensing and raster processing are analysis oriented. Continuous spatial overlap, proximity
etc. and ''landscape'' wide statistics are easily calculated. Spatial analysis is simpler
in raster form. GIS and vector processing are usually database management oriented.
Analysis of network inter-relationships, that involve topological elements, is more
natural in vector form. Element length, area, perimeter etc. are explicitly defined (this
is hard to do in raster systems!)

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