Re: Graphing Software

[Doug Craigen <dcc@ESCAPE.CA>]

"Robert L. Fenstermacher" wrote:
> We are looking to buy a more sophisticated graphing and analysis
> software package for both student and faculty use in the department.
> (We currently get by with Quattro Pro, Graphical Analysis, and Pasco's
> Science Workshop software.)  The two most recommended packages seem to
> be SigmaPlot 2000 and Origin 6.0.  Can anyone share their impressions of
> these, or suggest other alternatives?  Thanks.

Sigmaplot is a fine program.  I've used it both for data
summary/analysis and making up large panel graphs for publishing.  I've
also taught it and MathCad to students and the students prefer to use
Sigmaplot.  The fact that it is based on a spreadsheet seems to make it
easy to learn.

I've not used Origin.

One other program you might look into is Matlab (MATrix LABoratory) - or
its open source counterpart Octave.  This seems to be less known by
physicists (I learned it while working with electrical engineers), but
I've stopped using anything else for numerical analysis and graphing.
It does cost a lot more for Matlab than Sigmaplot (though the student
version is only $99). (Octave is free but not as fast or fullfeatured
and uses Gnuplot for graphics - still "the price is right").  For what
its worth, here's a quick run down:

In Matlab all variables are matrices by default.  You could plot a
simple straight line of slope one with:
x = [0 0; 1 1; 2 2]
plot(x)

or if you prefer
x = [
0 0
1 1
2 2
]
plot(x)

... simple enough for students to use I would say.  However the
capabilities are incredible beyond that.  It is deceptively simple when
you enter and simply have a command line, but is what you can do with
that command line...  Anthing that can be formulated as a matrix problem
(3D surface plots, FFT's etc) runs very efficiently.  My only complaints
are:
* they require you to do everything from either the command line or
scripts.  Once a graph is in place I would sometimes like to be able to
click on parts to open up a dialogue box to modify them.  Modifying from
the command line is very powerful, but not always convenient.
* the display is not WYSIWYG.  Both the screen display and the printout
are high quality, but they are not identical.  The ability to modify
them independently has its ups and downs, but I would like at least a
print preview of the printout to be available.

If you want to try the basic environment, download Octave:
http://www.che.wisc.edu/octave/
(Windoze 95/NT, SunOS, HP-UX, Digital Unix, OS/2 and Linux binaries are
available - maybe one of you Mac fans would like to take the source and
port it there.)

You can get an instructor evaluation copy of Matlab from
http://www.mathworks.com/products/studentversion/instructor_eval.shtml
Matlab has a large range of toolboxes to extend its libraries into areas
such as fuzzy logic, wavelets, image processing...


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Doug Craigen
          http://www.dctech.com/physics/