Geographic Information System (GIS)

Launch Geographic Information System
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A Geographic Information System (GIS) is mapping software that links information about where items are with descriptive information about the items. Unlike a paper map, where "what you see is what you get," a GIS map can combine many layers of information.

To use a paper map, all you do is spread it out before you. It is a representation of roads, mountains, rivers and political boundaries.

The power of GIS over paper maps is the ability to select the information you need to see according to your goals and this is achieved by the use of a database.

As on the paper map, a digital map, created by GIS, will contain lines that represent features such as roads and streams; and polygons that represent features such as lakes or property parcels.

The difference is that with GIS, each piece of information in the map sits on a layer, and the user turns on or off the layers according to their needs. One layer could be made up of all the roads in an area. Another could represent all the lakes or streams in the same area. Yet another could represent all the property parcels.

In addition to the geographical representation that GIS contains, the database contains tabular descriptions of each of the items. This data may include where a point is located, how long a road is, or the acreage of a property parcel.