v.* vector commands.;
More than 365 modules are available, for the most different purposes, from spatial analysis to environmental modelling, from thematic maps generation to DBMS integration, and 2D or 3D data visualization. The number of modules is constantly increasing, due to the possibility to access the source code.
GRASS can handle both vector and raster formats: exchanging data with other GIS is possible using interchange formats like TIFF, gif, IMG, ASCII, ARC/GRID (raster) or DXF, ESRI-E00, ESRI-SHAPE, ASCII, MapInfo (vector) and many more.
A World Wide Web interface called GRASSLinks to distribute GRASS data through internet has been developed by the Research Program in Environmental Planning and GIS (REGIS) of the University of California, Berkeley. This system provides visualization and analysis tools, allowing data sharing and cooperation between users through the internet.
Supported hardware platforms are Linux, Sun Solaris, Silicon Graphics Irix, HP-UX, DEC-Alpha, and Windows 95/98/NT/XP. GRASS developement is based mainly in Linux/Unix environments, so this is the most appropriated "habit" for GRASS usage.
For installation, GRASS requires at least 30 Mb of disk space for the precompiled binaries, the source code package needs around 100 Mb uncompressed; the resulting binaries may need between 80 Mb and 180 Mb depending on the platform, but during a full compilation you need temporarily 550Mb including the source code. 32 Mb of RAM are required (128Mb recommended), and be sure to have at least 500 Mb available on disk for data storage! Some libraries must be installed in order to use all GRASS modules: libtiff, libjpeg, libz for TIFF image importation, libTcl/Tk for the graphic interface, Mesa-3.0 (openGL clone) and lesstif (MOTIF clone).
Didactics with GRASS in the world
GIS GRASS has been adopted in many American and European universities. On-line well-made tutorials are available.
One is the Spatial Analysis course of the Delaware University, where main GRASS commands are described and a particular section is dedicated to UNIX-like operating systems first time users. At the end of the tutorial some exercises are proposed to the users: mining analysis, habitat analysis, hydrological analysis using DTMs, remote sensing and image processing. All required files to do these exercises are inside the SPEARFISH dataset (9.7 Mbytes): a group of raster, vector and sites map of the South Dakota, available for both 4.x and 5.x versions of GRASS on the site http://grass.itc.it/download/.
Spearfish dataset uses UTM projection system. On the same page you can find the IMAGERY dataset, including aerial and SPOT satellite images (19.1 Mbytes).
Finally some smaller datasets allow users to experiment some particular GRASS modules, like fire simulation r.ros, r.spread e r.spreadpath commands: to try them download the "Fire simulation dataset" (145kBytes).
Another GRASS tutorial is the one created by the ASSIST Project (Academic Support for Spatial Information Systems) of Leicester University, which is rather old (it's still based on GRASS 4.x) but well structured.
This tutorial is composed by four didactic modules: each one has a duration of two hours, with a little test at the end of every chapter. Lessons and exercises are about population distribution, soil usage, roads and railroads, rivers, DTM, satellite images. It can be downloaded here.
A last tutorial, useful for german language users, is the one of the Geology Institute at Freiburg University.
At this point the former first time GRASS user has now become an expert GRASS user, and can use this GIS to study more complex situations: good examples are the Spatial interpolation, Territorial analysis and Erosion models modules elaborated by the Geographic Modeling Systems Laboratory of Illinois University at Urbana-Champaign, and the module for the automatic detection of outlayers in digital surfaces, developed by the Geomatics Laboratory of the Milan Politecnico.
Proceedings of the GRASS Italian User Meeting are available in English in Geomatics Workbooks here.
= current link needed
This page is modified from What is GRASS?