There may be several different types of data in a GIS. Some of the data is direct spatial data, i.e., data elements that describe the position and geometric form of spatial objects, such as a city or state. Then there may be data that is related to the spatial data but is not inherently spatial; this is called attribute data. The attribute data may or may not be directly linked to the spatial objects.
There usually is base data that can be used as a locational framework for other data. An example would be a map of Georgia or the southeastern U.S., that can be used to locate some other spatial data, e.g,. the Chatuga river watershed. Another type of base data is an electronic gazetteer. This links the names of locations to spatial coordinates to allow users to ask such questions as "What are all the rivers within 50 miles of Atlanta?"
Then there may be application specific data, such as temperature, population, telephone lines, etc.
Last modified on March 02, 1999, G.
Scott Owen, firstname.lastname@example.org
GIS: Table of Contents
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