GRASS stands for Geographic Resources Analysis Support System.
Commonly referred to as GRASS, this is a Geographic Information System (GIS) used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization. GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies.
It is the most complete free GIS application available. It can be used both in command line and GUI mode. Integration with Quantum GIS provides further user-friendliness. Its ability to work in conjunction with the free statistical application R (by means of the package "spgrass6") is particularly interesting for research applications.
GRASS versions exist for Windows and Mac, but as it is mainly developped for Linux, it is recommanded to use it on a Linux system or through a virtual machine.
Quantum GIS (QGIS) is a user friendly Open Source Geographic Information System (GIS) that runs on Linux, Unix, Mac OSX, and Windows. QGIS supports vector, raster, and database formats. QGIS is licensed under the GNU General Public License. QGIS lets you browse and create map data on your computer. It supports many common spatial data formats (e.g. ESRI ShapeFile, geotiff). QGIS supports plugins to do things like display tracks from your GPS. QGIS is Open Source software and its free of cost.
Download from http://www.qgis.org
gvSIG is a tool oriented to manage geographic information. It is characterized by a user-friendly interface, with a quick access to the most usual raster and vector formats. In the same view it includes local as well as remote data through a WMS, WCS or WFS source.
It is aimed at users of geographic information, whether professionals or civil servants (city councils, councils, regional councils or ministries) from any part of the world ( at the moment its interface is in Spanish, Valencian, English, Basque, Gallego, Czech, Chinese, French, German, Italian, Romanian, Polish and Portuguese), in addition to being free.
Given its Free Software nature (open source) it is highly interesting for the international community of developers and, in particular, for university settings due to its R&D&I component. In fact, special emphasis has been placed on the expansion of the project so that potential developers can easily expand the functions of the application, as well as develop completely new applications from the libraries used in gvSIG (as long as they comply with the GPL license).
Download from http://www.gvsig.gva.es
The goal of uDig is to provide a complete Java solution for desktop GIS data access, editing, and viewing. uDig aims to be:
- User friendly, providing a familiar graphical environment for GIS users;
- Desktop located, running as a thick client, natively on Windows, Mac OS/X and Linux;
- Internet oriented, consuming standard (WMS, WFS, WCS) and de facto (GeoRSS, KML, tiles) geospatial web services; and,
- GIS ready, providing the framework on which complex analytical capabilities can be built, and gradually subsuming those capabilities into the main application.
Download from http://udig.refractions.net/