D.LEGEND GRASS GIS SOFTWARE

Recent versions of QGIS can be executed within the GRASS environment, allowing QGIS to be used as a user-friendly graphical interface to GRASS that more closely resembles other graphical GIS software than does the unique shell-based GRASS interface. There is cooperation between GRASS and Quantum GIS (QGIS). wxGUI is designed using Python programming language and Python graphical library.

GRASS 6.4.0 introduces new generation of graphical user interface called wxGUI. The GRASS modules are designed under the Unix philosophy and hence can be combined using shell scripting to create more complex or specialized modules by a user without knowledge of C programming. The GRASS libraries and core modules are written in C other modules are written in C, C++, Python, UNIX shell, Tcl, or other scripting languages. There are over 300 core GRASS modules included in the GRASS distribution, and over 100 add-on modules created by users and offered on the GRASS web site. The majority of GRASS modules and capabilities can be operated via a graphical user interface (provided by a GRASS module), as an alternative to manipulating geographic data in shell. All GRASS modules read this state and additionally are given specific parameters (such as input and output maps, or values to use in a computation) when executed. The environment has a state that includes such parameters as the geographic region covered and the map projection in use. Unlike typical application software, upon starting GRASS, the user is presented with a UNIX shell containing a modified environment that supports the execution of GRASS commands (known as modules). GRASS is designed as an environment in which tools that perform specific GIS computations are executed. This is in contrast with OpenGIS Simple Features, which define vectors more freely, much as a non-georeferenced vector illustration program does. The vector data model is topological, meaning that areas are defined by boundaries and centroids boundaries cannot overlap within a single layer. GRASS supports raster and vector data in two and three dimensions. GRASS is one of the eight initial Software Projects of the Open Source Geospatial Foundation. The GRASS Development Team is a multi-national group consisting of developers at numerous locations. It also supports Linear Reference System. GRASS supports an extensive range of raster and vector formats through the binding to GDAL/OGR libraries, including OGC-conformal ( Open Geospatial Consortium) Simple Features for interoperability with other GIS. The system is capable of visualizing 3D vector graphics data and voxel volumes. dbf files or SQL-based DBMS such as MySQL, PostgreSQL/ PostGIS, and SQLite. The recent GRASS 6 release introduces a new topological 2D/3D vector engine and support for vector network analysis. They can also interface with the modules directly through the modified version of the shell that the application launches or by calling individual modules directly from a preferred shell (this latter method requires the setting of several environment variables). Users can interface with the software features through a graphical user interface (GUI) by using the internal GUI with X Window System or by 'plugging into' GRASS via Quantum GIS.

D.LEGEND GRASS GIS MAC OS

GRASS is released under the GNU General Public License (GPL), and it can be used on multiple platforms, including Mac OS X, Microsoft Windows (natively or with optional Cygwin tools) and Linux. GRASS GIS ( Geographic Resources Analysis Support System) is a free, open source geographical information system (GIS) capable of handling raster, topological vector, image processing, and graphic data.

D.legend grass gis