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Image Processing for GRASS GIS

Graphical User Interface

The older version of GRASS is written in TCL (Tool Command Language). The new generation of GRASS 6.4.1 brings a number of improvements to the GIS and is integrated with Python programming language using wxPython graphical library. The user interface of both the old and new versions is shown in Figure 1.1.

old_new_GUI

Figure 1.1: Graphical User Interface of GRASS Tcl/Tk (old) and wxPython (new)

When you start the GRASS and enter through, you can see the GUI is comprised of two main components as shown in figure 1.2 namely:

  • Layer Manager
  • Map Display Window.

layer_display_windows

Figure 1.2: The layer manager (left) and the map display (right) windows in GRASS GIS

The Layer Manager allows users to work on different elements from a menu, consists of map layer management, integrated command line prompt and command output window. Map display window composed of basic tools for zooming, data querying, legends etc. The wxPython graphical user interface will be used in this course as it has the advantage of speed and independence from command line interface over the old version.

Project Location - : A LOCATION is some geographic extent of interest that contains datasets in the same co-ordinate system. Every LOCATION has a PERMANENT directory, automatically created by GRASS to store basic information about the whole location. You can rename the LOCATION by accessing the folder from your computer drive. LOCATION and MAPSET are explained with its structure on GRASS Quickstart website.

More information about wxPython GUI, Layer Manager and Map Display window has been given on the GRASS website.

The steps for database creation have been covered in the subsequent sections with the datasets provided for the first unit titled Information Extraction.