GRASS: Introduction

Welcome, First time Users of GRASS!

The GRASS Wiki

• The GRASS community maintains a Wiki collaborative help site which contains getting started guides, tutorials, tips and tricks, FAQs, and a lot more. See the Getting Started and First Day Documentation sections of the main help page. The information on the wiki will generally be more up to date than the information found on the web pages, as migration, consolidation, and updates are a continual work in progress.

Some new users questions

• Under which platforms can I work with GRASS?
• What can I do with GRASS?
• Does GRASS support SQL databases?
• What do I need to run GRASS GIS?
• Where can I download GRASS software?
• How can I get my data into GRASS?
• Where can I find documentation on GRASS?
• What are LOCATIONs and MAPSETs?
• Are there GRASS tutorials and sample data?
• I know GRASS already and want to program within the GRASS environment
• I downloaded GRASS - but what now?

Under which platforms can you work with GRASS

GRASS is developed in a UNIX environment and is ported to many other systems like:

• UNIX environment through a graphical user interface and shell in X-Windows
• MS-Windows (NT/2000/XP with Cygwin) for the experimental winGRASS port
• MacOS X

What can I do with GRASS? - Some examples

• See our growing Applications and Screenshots page. Here you will find many examples on Applications and Institutes using GRASS, including an image gallery and reports.
• Check out the new 3D raster volume format. It comes along with a 3D raster map algebra module, 3D volume interpolation, and other features. You can also export the GRASS 3D data to Vis5D visualization tool.
• Maybe you are interested in one of the many GRASS GIS related projects and libraries, such as MapServer, GDAL, PostgreSQL, OGR, libgrass, PROJ4 etc..
• Or have a look at the NVIZ 3-D GRASS Interface.
• Get information about the GRASS 6 development.
• There also exist many external packages for GRASS called Add-ons.
• GRASS as a modular based GIS offers a wide range of possibilites to build professional solutions. The figure below is an example how grass can be used with other applications

Does GRASS support SQL databases?

What do I need to run GRASS GIS?

NOTE: You can also install Linux or another operating system in its own hard drive partition and run a Windows system parallel in another hard drive partition.

• GRASS binaries need around 50-80MB space
• GRASS sources need around 100MB+.

Looking for the GRASS software to download?

• Please proceed to our download page.
  Here you find all information on Binaries, Sources, CVS access, installing, compiling, etc.

Well, I can't get my GIS data into GRASS! What now?

• A good idea is to read the GRASS 5 data import and also the GRASS 5 data export help pages. As GRASS supports a wide range of image, raster, vector and sites data formats, you will probably find some module handling your data.
• From the GRASS online manual pages you can get all information about modules, etc.
• Besides this you may always ask at one of the existing GRASS Users mailing lists - don't hesitate!

The GRASS Documentation Project

The documentation in GRASS is managed within the GRASS Documentation Project (GDP). The idea is to collect all the online documentation available for GRASS in one space. The GDP is devided into 6 sections:

• General/Features (descriptions on GRASS modules, FAQs, related articles etc.) and Manual pages (GRASS commands and manual pages)
• Books, Tutorials (Tutorials in english, italian, german etc.) and GRASS Courses in english, german, japanese)
• Install/Prog (Documentation on Installing and Programming GRASS)
• Special Topics (DBMS, modeling, analysis etc.)

What are LOCATIONs and MAPSETs?

In a MAPSET you can organize GIS maps thematically or geographically or by project or whatever. Every GRASS session runs under the name of a MAPSET. A MAPSET may be a geographical subset or as large as the parent LOCATION. Technically they are subdirectories under any location. In a networked environment with several users working within the same location, mapsets play a special role. Users may only select (and thus modify) a mapset that they own (i.e., have created). However, data in all mapsets for a given location can be read by anyone (unless prevented by UNIX file permissions). The "PERMANENT" mapset usually contains the read-only base maps like the elevation model, while the other locations are readable and writable by their owners. The "PERMANENT" mapset also contains some information about the location itself that is not found in other mapsets (projection info etc.), thus it must exist in every location.

Putting LOCATIONs on a central server, a team can work inside this project database (usually NFS is used).

Looking for GRASS tutorials or sample data?

• There is an online Books and Tutorials Collection available inside the GRASS Documentation Project (GDP). Here you find links to existing GRASS Tutorials in english and several foreign languages (german, italian, korean and polish).

• We also provide further sample datasets including data which are already in GRASS format and ready to use and links to external GIS data (raster, vector etc.).

I know GIS already and want to program within the GRASS environment

• As GRASS is an open source GIS, so you have full access. We suggest that you get a fresh copy from the GRASS CVS repository.
  Consider to subscribe to the GRASS Developers mailing list.  The GRASS Programmer's Manual is available here.

• If you would like to take part in the GRASS Development. See also the Get Involved! page.

I downloaded GRASS - but what now?

• GRASS is running in a session. The data are stored in a so-called "location" which is effectively a collection of subdirectories. When running GRASS, you have to define or load such a location which contains the data as well as projection definitions.
• To start with own data, create an emtpy directory within your home directory. For example, call it "grassdata". This directory is where GRASS will create and store its database.
• To warm up, we strongly recommend to start with sample datasets!.
  A good idea is to download the Spearfish data containing raster, vector and point data of South Dakota. There is also described how to start GRASS with the SPEARFISH dataset.
• After extraction of the sample data set in the "grassdata" directory, start GRASS: 
  grass5 or grass43 
  in your terminal.
• Enter a name for the project area ("location") and subarea ("mapset"). The mapset extent can be the same as the location extent (the best is to enter your own name here). Enter the path to your "grassdata" directory. Example (see startup screen):

• In this example GRASS would be started in the spearfish location under the mapset emil. You can now start working (open a X-window with d.mon start=x0, visualise a raster map with d.rast etc.), but at this point you should refer to one of the GRASS Tutorials or other help available on the GRASS pages.