The NGDS Data Explorer is designed to interact with, and extract data from, GIS attribute tables. This section describes GIS attribute tables.

Geographic Information Systems are software applications designed to access, visualize, and analyze geospatial data. Most GIS applications approach this objective by combining cartographic software, database software, and statistical analysis software in one package.

ESRI ArcGIS is a well-known GIS application that represents real-world objects as cartographic features. Each feature in an ArcGIS document is described by a database record; each database record contains attributes, including the latitude-longitude position of the feature and other relevant information. This database, or attribute table, can be queried and used to perform statistical analysis.

For example, an ArcGIS attribute table might contain data describing features such as homes, power lines, and power plants in a given state. This attribute table would permit these features to be projected and displayed accurately on a map. In addition, if the attribute table contained information on power usage rates over time for each house in the dataset, it could be used to perform geospatial analysis on power usage in the area, in order to anticipate demand at any given location.

Web feature services (WFS), described further on the next page of this tutorial, use attribute tables; the NGDS Data Explorer is designed to query these attribute tables and extract data from them.

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