Geographic Information Systems (GIS) can capture, organize, analyze, and spatially map data. The value of a GIS is that all the data contained inside the system has a spatial relationship to the Earth (or coordinate system of reference) and that data can be compared to other data that share that same location. GIS basically builds a "data sandwich" in that data can be layered over each other even if they are at different resolutions or scales. Once the data is geographically referenced, it knows it's place in space. GIS have both cartographic (mapping) capabilities and also databases that can store additional information about each object in the system. Therefore, when you analyze in a GIS, you can pull information at once from many different layers and their corresponding data. GIS puts together spatial analysis with database analysis. Many entities use GIS to discover data relationships that may be hard to find on paper maps or through tabular databases.

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• Geographic Information Systems (GIS) in Rhode Island
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• The Role of GIS in the National Gypsy Moth Slow the Spread Project (STS)
• Topography and Understanding Topographic Maps