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Data Visualization using Perl/Tk
Idean writes "Generating a visual representation is often the best way to understand large data sets, but standard tools such as gnuplot often fall short. This article shows how to use Perl/Tk, the standard GUI toolkit for Perl, to quickly build custom plotting and graphing tools."
I don't see the point in using Perl and Tk to write you own scientific plotting software. There is already plenty of software out there to do this, and it's better written and tested than anything one would produce in an afternoon with Perl and Tk.
The last thing you need when exploring large and complex data sets is to find that the code you are using to visualise the data is buggy! Don't roll your own!
I use Matlab for my work, and it has a fantastic range of scientific plotting features. It's not cheap, but there are some good free/OS packages too:
Look at:
gnuplot (http://www.gnuplot.info/)
KMatplot (http://kmatplot.sourceforge.net/)
GGobi (http://www.ggobi.org/)
Gri (http://gri.sourceforge.net/)
There are others, too.
I do not consider the data that was used in the example to be complex or large, and I don't see how Perl could help, as numerical processing is certainly not its strength!
Perl may be useful for massaging data into a form that is accepted by a scientific visualisation package, however.
"The noble art of losing face will one day save the human race"---Hans Blix
And how did your control group do?
What language was Perl compared to using this methodology?
Did the test subjects have experience with Perl? And, what of the control group?
Perl is different, no doubt about it. But, it doesn't *have* to look like line noise.
--Phillip
Can you say BIRTH TAX
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
If you're a good programmer, you can read the line noise.
At the same time, a good perl hack wouldn't write unreadable code. I often rewrite a complex operation, breaking it into 3 or 4 step, out of courtesy to the poor schmuck who has to maintain the code.
"Faith: Belief without evidence in what is told by one who speaks without knowledge, of things without parallel." - A.B.
Examples of complicated graphs include specialized bar-and-whiskers plots
I had to cope with box-and-whisker plots to visualize data gathered from a statistical survey. Frankly, Perl/Tk was nothing I looked into (and I love Perl & Tk!). I entered the data into an OpenOffice spreadsheet (which made the statistical calculation very easy!) and googled for a solution. There are many commercial packages available for Excel, but this article was really helpful. I managed to create a similar solution for OO (I'm not sure if the result is of interest to anyone - if so, msg me or something).
Does anyone know a repository for statistical analysis programs? Because if you only need to run an analysis once, you think twice about hacking a Perl/Tk program (the 'clean' approach) unless you are a true Perl wiz - the time needed to write the program is (with my programming abilites) two or three times longer than looking for another one shot solution (the 'practical' approach).
If there was a central repository for this, you a) knew where to look first and b) had an incentive to write the program to save someone else the time. Yes, I know I could put it up to some website, but I really doubt anyone would find it or even look for it...
My cats ate my karma. They also wrote this comment.
If you want statistically sound data analysis and graphing, look no further than the R Project. It's a complete programming environment and is extensively used by working statisticians.
Python, Numerical Python, various Python plot packages, and VTK also make for very powerful visualizations if you want something more do-it-yourself.