Geographic Information Systems (GIS) analysis often uses raster datasets. While vector datasets are represented by points, lines, and polygons and contain an attribute table, raster datasets are structured instead as an array of cells, or pixels. Geographic Resources Analysis Support System GIS dates back to 1982 and is an open-source program that was originally created by the US Military. Quantum GIS (QGIS) is installed as an application, just like ArcMap or other desktop GIS. QGIS is a desktop GIS program, just like ArcMap, with many of the same features as ArcMap. Although the tools within QGIS and ArcMap might have different names, GIS professionals can usually accomplish the same tasks in both QGIS and ArcMap, though the speed of completing tasks may differ. The Geospatial Data Abstraction Library is an open-source software library that dates back to the year 2000 and powers raster analysis in several programs, both proprietary and open source.