測繪專業(yè)畢業(yè)設(shè)計(jì)中英文文獻(xiàn)gis(文件)
【正文】 ue areas similar to the real lakes . A digital map is not much more difficult to use than a paper map. As on the paper map, there are dots or points that represent features on the map such as cities, lines that represent features such as roads, and small areas that represent features such as lakes . All this information— where the point is located , how long the road is, and even how many square miles a lake occupies— is stored as layers in digital for m at as a pattern of ones and zeros in a puter . Think of this geographic data as layers of information underneath the puter screen. Each layer represents a particular the m e or feature of the map. O ne the m e could be made up of all the roads in an area. Another me could represent all the lakes in the same area. Yet another could represent all the cities. These themes can be laid on top of one another, creating a stack of information about the same geographic area. E ach layer can be turned off and on, as if you were peeling a layer off the stack or placing it back on. You control the amount of information about an area that you want to see, at anytime, on any specific map. The technology ponents of a GIS can be explained interims of hard ware, software and human resources. GIS hard ware includes: puters, puter configuration/ works, input devices, printers, and storage systems. Computers for GIS usage can be P Cs or superputers. These puters can be standalone units or can be hooked into a work environment. Input devices include digitizers and scanners. Printers and plotters are used to produce a hardcopy map. GIS storage systems include: optical disks, magic disks (such as a hard drive), floppy disks or magic tapes. GIS software includes both GIS program and special application packages, such as digital Terrain modeling and work analysis. The main difference between GIS software programs and desktop mapping programs is the ability of GIS programs to perform spatial analysis. ARC/ INFO by Environ mental Systems Research Institute (ESRI) Inc. is one of typical examples of GIS software packages. Desktop mapping programs offer m any of the same features, as a GIS, but their ability to support spatial analyses are limited. They are developed to satisfy individual user needs for mapping presentations. MapInfo developed by MapInfo Corp is an example of popular desktop mapping programs. Human resources used to operate a GIS typically include: ope
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