Open Source GIS

I've been asked a number of times about open source alternatives to traditional commercial GIS. It's a good question. There is so much to choose from in the open source community. Commercial GIS packages (ESRI, Autodesk, MapInfo, Integraph, Manifold) are very powerful, offer a range of development options, provide other supporting products for a complete enterprise solution (database, web, mobile), yet may be very expensive and burdensome to accomplish simple tasks.

Free and Open Source (FOSS) GIS has reached a mature enough stage in recent years that it may be a more efficient alternative to commercial GIS in some instances. With the exploding popularity of geo-applications and the concept of location being engrained into many arenas, incorporating the current IT climate of smaller, faster, cheaper applications, open source GIS should garner serious consideration from any GIS user. In fact, FOSS software have been identified as COTS software by many organizations (US Navy for one) and is considered alongside any proprietary, commercial solution.

Listed on this page are what I believe to be the main FOSS players in geospatial work. These programs usually have large user communities, are mature in stability and functionality, and have relatively easy installation procedures. There are many other FOSS products and by no means is a comprehensive list. There are also many free, non-open source (Free As In Beer) software that offer similar functionality (such as our list of GeoViewers, or Oracle Express Spatial, or Google Maps API) and may play a large role in a any geospatial solution..

Also note, these packages can always be used in conjunction with commercial packages, for example, Manifold GIS connecting to a PostGIS database, adding a GDAL raster format to ArcGIS Desktop, or using a ArcGIS/ArcView extension to create a .map file for MapServer.

Desktop GIS, Image Processing, and Analysis

Quantum GIS (QGIS) - desktop GIS
GRASS GIS - desktop GIS and analysis system
OSSIM - image processing
uDIG
gvSIG
OpenJUMP
SAGA GIS - image processing, geostatistics
MapWindow GIS
R Statistics
mezoGIS - map interface for PostGIS SQL queries

Web Map Servers and Clients

MapServer - WMS web map server
GeoServer - WMS, WFS, WCS web map server
FeatureServer - WFS web map sever
OpenLayers - web JavaScript API
MapGuide Open Source
Community MapBuilder - web javascript API
MapBender - server-side web GIS client in PHP
ka-Map - client for WMS server

Development

FWTools - a set of Open Source GIS binaries for Windows and Linux
OGR/GDAL - libraries for reading and writing geospatial data
GeoTools - Java toolkit for building GIS apps
GEOS - Geometry Engine, Open Source
FDO - Feature Data Objects Data Access Technology
PROJ4 - Cartographic Projections Library

Portal/Clearinghouse

Database

3D Viewer

NASA World Wind

Online resources on Open Source GIS.

Books, Journals, Publications

More Info on FOSS Geo

For more information about products and standards, and a more comprehensive list of free and open source geospatial software, check out the following: