Software
General aspects on GIS and RS software
A variety of GIS and RS software packages is available on the market. They may be categorized according to two sets of criteria:
1) The license terms, visibility of the source code and distribution policy
- proprietary software packages do not allow to view the source code of the funcionalities. Therefore, further development of the software is only conducted within the company owning and distributing the product. Use of the GIS software is coupled to the purchase of a licence for single users or organizations. License fees are often paid on an annual basis.
- Open Source software packages: the source code is accessible, so that anyone can contribute to the further development or design additional modules serving for her or his specific needs. Usually, there is a community developing the software. Open Source software packages are often (but not always) distributed under the GNU General Public License, meaning that they are free, but certain rules must be followed when distributing work building on the software. Most OpenSource software packages were designed for UNIX sytems, but they are increasingly adaptred to the Windows environment. The Open Source Geospatial Foundation (OSGeo), which coordinates much of the software development, provides a comprehensive list of Open Source GIS software packages.
2) The functionalities offered by the software
- specialized software: many GIS software packages are specialized to a certain set of functionalities, e.g. raster analysis, vector analysis, processing of remotely sensed data, display of maps, online map services or the integration of databases. This is particularly true for many Open Source GIS software packages.
- comprehensive software: some packages offer a wide range of functionalities. Most of them have started with a certain set of functionalities a long time ago, which are still the core of the software today. ArcView, and later ArcGIS, for example, were originally designed for vector analysis, but extensions were added to allow operations on raster data.
Selected software packages
The below list contains a selection of software considered to be useful for application in geosciences. It is not complete, and many specialized software packages are disregarded. Such include, for example, databases, Web GIS software or programs for field computers and GPS. Particularly the latter are extremely useful for geological field work, a topic not covered by the present training course.
Software
Description
License terms
Functionality
Originally developed by the US Government in the 1970s and being focussed on raster analysis, GRASS GIS has evolved to a comprehensive package offering a variety of toolsets for raster and vector operations, display and general GIS functionalities. It is developed by a community, the physical home of the software changes from time to time. Though it is designed for UNIX, a version for Windows (without requiring Cygwin) is available. An advantage of GRASS is that it allows a relatively easy automatization of analysis steps as well as the implementation of completely new functionalities.
Open Source
Comprehensive
Quantum GIS (short QGIS) is a comprehensive package offering a variety of GIS functionalities including map layout. Like GRASS, it is an official project of the Open Source Geospatial Community (OSGeo) and developed by an active community. Versions exist for various platforms.
Open Source
Comprehensive
Like GRASS GIS, SAGA GIS is a quite comprehensive Open Source GIS software. It runs on Windows and UNIX platforms, the development centre has recently moved from the University of Göttingen to the University of Hamburg. The software can be used as an alternative to GRASS GIS.
Open Source
Comprehensive
ArcGIS is the most used GIS software package. It offers a wide variety of functionalities and is very user-friendly. Among all existing GIS software packages, it has the most advanced functions for designing high-quality map layouts. ArcGIS is developed and owned by the ESRI Company. Its distribution follows a stringent and complex licensing scheme distinguishing three levels: ArcView (which has nothing to do with the old ArcView, see below), ArcEditor and ArcInfo, listed in order of increasing functionality and license fee. Extensions (e.g. Spatial Analyst, 3D Analyst) have to be purchased additionally. ArcGIS consists of different sub-packages the most important of which is ArcMap, where all spatial operations are performed. ArcCatalog is a data management software for spatial datasets. ArcScene allows the 3D display of data and only works if the 3D Analyst is installed.
Proprietary
Comprehensive
ArcView is also distributed by ESRI, it was the precursor of ArcGIS. Though it is a multi-functional and user-friendly program, it is not further developed and there may be severe compatibility problems with new versions of Windows.
Proprietary
Comprehensive
ERDAS Imagine is a widely used Remote Sensing software. It is specialized to basic and advanced operations on areial and satellite imagery, including geometric and radiometric correction, mosaicking, orthophoto generation, generation of DEMs by stereo matching of imagery and many more. The software is distributed and licensed by ERDAS, Inc.
Proprietary
Specialized
ENVI is a remote sensing software. The basic software package allows for standard GIS and RS procedures, but there are several additional modules designed for highly specialized tasks. SARSCAPE, for example, allows the processing of radar satellite imagery, including radar interferometry. ENVI and its modules are distributed and licensed by EXELIS Visual Information Solutions.
Proprietary
Specialized
PCI Geomatica is a Remote Sensing software, too. It can be used as an equivalent alternative to ERDAS Imagine, the functionalities offered by both programs are comparable. The software is distributed and licensed by PCI Geomatics, Inc.
Proprietary
Specialized