WhereGroup

Desktop GIS enables a wide range of users to process geospatial data and utilise a wealth of geospatial functionality based on comparatively cheap and readily available Personal Computers. Over time, Desktop GIS has become a typical example and a tendency to move from powerful centralised computing hardware to decentralised networks of PCs for geodata processing.

However, with the decentralization of processing, the administration of installation, maintenance and security aspects starts to grow disproportionately and GIS departments often raise requirements for excessive IT support.

Paradigm Shift

With the introduction of distributed architectures and web based processing services, the use of geospatial data has moved from its limited traditional application areas to a mainstream source of information.

At the same time the relevance of stand-alone desktop GIS products is steadily declining: whilst the total number of installed seats is more or less stable, most desktop GIS now plug into service oriented SDIs as datasources and thus combine the advantages of local processing capabilities with distributed architectures.

State of the Art

There are several dozen Open Source based Desktop GIS applications available to choose from, most of which are optimized for specific application areas. The relevant developments are mostly based on Java or C++ and provide a high degree of flexibility due to standardized interfaces and the capability to be deployed within service oriented architectures.

However easy it may seem at first glance, desktop GIS is a powerful tool and still requires a solid background and good training to unleash its full potential. Below we have compiled some information on the most commonly used Open Source based desktop GIS:

gvSIG

gvSIG is a comprehensive Desktop GIS software implemented in Java. It comes with a user friendly interface and gives quick access to most of the common geographic raster and vector formats. By supporting the OGC Standards WMS, OGC WCS and OGC WFS it can integrate remote data with local sources and can be used as a desktop client in spatial data infrastructures.

It is targeted at professional users of geographic information from the public sector, private industry sciences and education. It is developed as an Open Source project and currently undergoes the OSGeo Incubation process. The software provides internationalization modules and several languages are already supported.

gvSIG is protected by the GNU GPL Free Software license. Current emphasis of the project lies on improving outreach to developers who are interested in extending the functionality of the software and to provide interfaces to allow the development of completely new applications based on the libraries used in gvSIG.

Quantum GIS

Quantum GIS (QGIS) is a user-friendly Desktop-GIS, released under the GNU General Public License (GPL) and available for Linux, Unix, MacOS X and Windows operating systems in several interface languages.

Quantum GIS also acts as frontend user interface to the GRASS program and thus benefits from the huge number of features of this package.

Quantum GIS is implemented in C++ and includes Plug-In interfaces to extend the initial functionality. You can also use the software to configure UMN MapServer MAP-files, which reduces the effort needed to set up UMN MapServer map files.

GRASS

The Geographic Resources Analysis Support System (GRASS) is the most complex and professional Open Source based desktop GIS and is supplied under the GNU General Public License (GPL). Supported platforms include Linux, Unix, MacOS X and Windows. The strength of this GIS lies in its modular structure and its utility for raster processing and modelling.

Quantum GIS is the ideal add-on to GRASS, since it provides the user with a user interface to handle the wealth of functionality, which the GRASS modules provide. It is the modular structure which also positions GRASS perfectly for automised and scripted production processes for expert users.

Combining Quantum GIS, GDAL/OGR and GRASS likely covers all features and functions one would need for any given geospatial requirement.

uDig

The User-friendly Desktop Internet GIS (uDig) is a GIS applicationen that serves as viewer and editor for geospatial data that is served via OGC compliant WMS and OGC WFS. uDig is implemented in Java and based on GeoTools.

uDig is not only used as an 'off the shelf product', but provides an environment to implemenet solutions for domain specific applications. The software has been developed by Refractions Inc., Canada and is available under the GNU Lesser General Public License (LGPL).