Survey of Desktop Mapping Software - Desktop GIS: Mapping the Planet with Open Source Tools - page 260

GRASS

GRASS is written in C
with the GUIs
implemented using
TCL/Tk and Python.

Let's start with the patriarch of the OSGIS world—GRASS. The Geo-
graphic Resources Analysis Support System, or GRASS as its com-
monly called, is a GIS that supports analysis, modeling, visualization,
raster processing, and many other operations. It is the “heavyweight”
of the OSGIS world.

GRASS was originally developed by the U.S. Army Corps of Engineers
Construction Engineering Research Laboratories (USA-CERL) for use in
environmental research, assessments, monitoring, and management of
U.S. Department of Defense lands. The last release was in 1992 and
by 1996, USA-CERL was no longer supporting the public in its use of
GRASS. This began a transition period that in the long run gave us the
open source version of GRASS we have today.

Today GRASS has an international team of developers and users
throughout the world, including academia, government, and consult-
ing companies. If you are interested in more of the history, visit the
GRASS home page. 2

In Figure A.2 , on the next page, you can see a simple example of GRASS
with the countries of the world layer displayed on a raster background.

GUI or Not?
Is GRASS a GUI program or a command-line program? The answer is
both. Seriously, though, GRASS has a GUI component, but the real
work is done by a suite of command-line programs, or modules, that do
everything from import data to combining grids. The GUI side provides
both a means to view your data and to perform the many functions
that GRASS provides. So in reality, you can think of GRASS as a bit of
a hybrid with the power of the command line and the convenience of
a GUI. The individual programs can be glued together with a scripting
language (shell, Perl, Python, Ruby, your choice) to perform complex
operations.

The GUI is currently undergoing a bit of change with a new interface
being developed using Python and wxWidgets. 3 In addition, Quantum
GIS supports viewing of GRASS layers, giving you another option for
visualizing your data.

1. http://freegis.org

2. http://grass.itc.it

3. http://www.wxwidgets.org