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Introduction to GIS and formats

GIS

In order to work effectively with large quantities of data the use of geographic information systems (GIS) is necessary.

Geographic Information Systems (GIS) are a computer programs that organize, display, and analyze spatially distributed data. At its simplest, GIS is "mapping", providing a geographic arrangement of extremely diverse information. GIS has been applied in geology, biology, psychology, anthropology etc., and has been around in Crop Forecasting for a long time.

General purpose GIS programs are designed to capture and analyze any kind of geographical data. The most common commercial GIS software packages worldwide are:

However the open-source community has created a wide range of free tools (to be downloaded from the internet). A nice start page can be found here: http://www.mapcruzin.com/free_gis.htm

GIS data is commonly in one of two forms:

  • Raster: A grid of rows and columns of cells. These might represent photographic or scanned images.
Raster  format
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Raster format
  • Vector: geometric shapes, including points, lines, and polygons. These might represent buildings, roads, and counties.
Vector format
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Vector format

Either of these can have tables of data associated with them, e.g. elevation, population, financial values, etc. Such associated data can be used to color a map so that it conveys information with visual impact.




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