Open Source GIS Software
The links provided do not represent a exhaustive list of geospatial technologies. Resources may include software, developer tools, and useful data.
No endorsement of any resource is implied. No support for any of the resources is offered. Users are encouraged to investigate the licensing and fair use of each site, company, organization, or agency.
QGIS
Quantum GIS (QGIS) is a powerful and user friendly Open Source Geographic Information System (GIS) that runs on Linux, Unix, Mac OSX, Windows and Android. QGIS supports vector, raster, and database formats. QGIS is licensed under the GNU Public License.
GRASS GIS
GRASS GIS, commonly referred to as GRASS (Geographic Resources Analysis Support System), is a free and open source Geographic Information System (GIS) software suite used for geospatial data management and analysis, image processing, graphics and maps production, spatial modeling, and visualization. GRASS GIS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies.
MapWindow
The MapWindow GIS project includes a free and open source desktop geographic information system (GIS) with an extensible plugin architecture; a GIS ActiveX control; and C# GIS programmer library called DotSpatial.