QGIS is a popular GIS platform that parallels the functionality of ArcGIS in many respects.  Notably, QGIS has the benefit of being free and open source as well as cross-platform. It is available for Windows, MacOS, BSD and Linux operating systems.   In fact, QGIS may be better described as a desktop platform that leverages a collection of open source tools.  Most installations will include SAGA, GDAL and GRASS tools.  Users may also access R, the Orfeo Toolbox and hundreds of other external plugins created by the QGIS community.

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