Introduction
gd is
a command-line oriented data plotting progam for computers running the UNIX or similar
operating systems. The data can be 1- or 2-dimensional.
The basic idea is that data to be plotted as well as
layout instructions reside in a single text file in free format.
These text files can be viewed by any file browser and edited by any text editor.
In most cases only two commands (a read and a display) are sufficient
to generate a graph of the data. Because many layout items are defaulted
to "reasonable" values it should be rather easy to generate pictures
without too many user interventions. Complex pictures can be built
by overlaying new pictures on an already existing plot.
Data can be presented with various symbols, connecting lines, linewidths and colours.
Text can be added at arbitrary positions in any size, direction and colour.
Special symbols including math and greek characters are supported.
Graphic elements like extra lines, arrows and other geometric figures may be added to a plot.
gd provides means to influence the layout of
the picture (colours, linewidths, text sizes etc.) at various levels,
either interactively, as a session default or in the data files.
A function fitting package is attached to allow least squares optimization
of builtin and user defined functions.
gd supports command scripts so that complex pictures can be built
by grouping several commands in a single script file which can readily
be executed rather than typing individual commands.
Graphics output can be on any X-server for display or PostScript printers for paper copies.
Encapsulated PostScript files can be used later in word processors like TeX
Historically gd is a derivative of the satangd program which once ran
on GSI's MVS mainframe computer. Hence most legacy data and script files can be
recycled.
gd isn't
a free hand graphics program, a word processor or an image processing program,
although a few features of such programs have been incorporated.
For example, it is possible to add graphics elements to a picture,
you can add text in formatting mode and there is some support to read and display bitmap files.
However, for specific tasks you should rather use dedicated software
like xfig, TeX or xview, respectively.
Availability
gd is available for a variety of platforms
- IBM RS/6000 (AIX )
- HP/9000 PA-RISC (HP-UX)
- HP/9000 68k (HP-UX)
- Sun SPARC (SunOS,Solaris)
- x86 (Linux)
- SGI (Irix)
- DEC Alpha (DEC UNIX aka Tru64)
- DEC Mips (Ultrix)
- Amiga 68k (AmigaOS)
- Apple Mac (Mac OS X, X11 required)
Versions for OS/2 are in preparation.
At GSI, gd is installed on the central AIX and Linux computers.
For use outside GSI an export package (tar'ed and compressed) is available
on GSI's ftp server or
here.
It comprises the executable, shell scripts,
tutorial data and documentation in HTML and system specific format.