Introduction to Grass - GIS



GRASS GIS (Geographic Resources Analysis Support System) is an open source, free Geographical Information System (GIS) with raster, topological vector, image processing, and graphics production functionality that operates on various platforms through a graphical user interface and shell in X-Windows. It is released under GNU General Public License (GPL).



Surfing the web

Use key words 'grass' and 'gis' in your prefered wed browser to find out all the web sites you need. However, the official web site is the best starting point.

For french people, use the mirror-site



What is grass ? (exerpt from the official site, dec. 2001)

General Information Geographic Resources Analysis Support System, commonly referred to as GRASS GIS, is a Geographic Information System (GIS) used for data management, image processing, graphics production, spatial modelling, and visualization of many types of data. It is free software released unter GNU General Public License (GPL).

Originally written by the U.S. Army Construction Engineering Research Laboratories (USA-CERL) branch of the US Army Corp of Engineers as a tool for land management and environmental planning by the military, GRASS has evolved into a powerful utility with a wide range of applications in many different areas of scientific research. GRASS is currently used in academic and commercial settings around the world, as well as many governmental agencies including NASA, NOAA, USDA, the National Park Service, the U.S. Census Bureau, USGS, and many environmental consulting companies.

The headquarters for GRASS support, research, and development are at ITC-irst (Trento, Italy) (was: University of Hannover, Germany, from 1998-summer 2001) and Baylor University (Waco, U.S.A.). However, due to the rapid growth and popularity of GRASS, the GRASS Development Team has grown into a multi-national team consisting of developers at numerous locations and now maintains dual headquarters in both the United States (Baylor University) and Italy (ITC-irst). The development currently underway has resulted in new GRASS versions, the release of new manuals and documentation, as well as continued research and development for new versions.

The GRASS GIS is run through the use of either a standardized command line input, or an intuitive Graphical User Interface based on Tcl and Tk. GRASS is also supported under Windows NT/2000 running Cygwin (experimental). GRASS can be used in shell scripts which allow users and programmers to create new applications and link GRASS to other software packages. For programming a fully documented C-API (> 800 GIS functions) is provided. Users can input new data through digitization, CD-ROM, floppy disk, or tape drive.

Operating systems/platforms supported

Architectures: Intel x86, Motorola PPC, SGI, MIPS, Sun SPARC, ALPHA AXP, HP PA-RISC, others.

Operating systems: Linux, Sun Solaris, Solaris x86, Solaris SPARC, SGI Irix, HP-UX, DEC-Alpha, PowerPC, MacOS X (Darwin), IBM AIX, BSD-Unix, FreeBSD, CRAY/Unicos and other UNIX compliant platforms (32/64bit), additionally Windows NT/Cygnus.

GRASS is written in C with documented C-API and offers a preliminary JAVA interface. Source code and selected binaries can be downloaded.

Data formats supported

2D raster data, 3D raster data (voxels), topological vector data (2D, currently extended to 3D) point data (called sites) In detail:

Data management capabilities

GRASS Programming As GRASS 5 is released under GNU GPL, the sources are released to public. GRASS provides a sophisticated GIS library which can be used for own developments. A "GRASS Programmer's Manual" is available for download.



Grass is used by hydrologists (exerpt from the official site, dec. 2001)

Total Water Quality Managementfor Distribution Systems

Bruce W. Byars, Hydrologist

Using techniques based on field data gathering, laboratory analysis, and model simulation techniques, a system for total water quality management has been developed. While the simulation techniques presented here do not take the place of sound engineering judgement, the techniques used here are a cost-effective method of insuring water quality at the distribution end of the system.

GRASS allows users to analyze, store, update, model, and display data quickly and easily. Although it was originally developed for use in land planning, its capabilities have been expanded and used in the fields of engineering, hydrology, geology, physics, statistics, remote sensing, business, and many others.

Questions regarding how GRASS can help in your work or on the operation of GRASS can be e-mailed to