[Matrix-SIG] Python Data Analysis and Plotting

Anthony L. Wilson wilsona@earthlink.net
Tue, 06 Apr 1999 10:43:51 -0400

This is a follow-up message to the response to the topic "Using Python
or Java for Data Analysis"

It seems that there are two promising projects that may be of use for
me: Snow and Piddle.  I am glad to see some work is still on-going in
this area.  In looking at the other packages(
http://www.python.org/topics/scicomp/plotting.html ), I could not find
one that would fit the bill for running on both Linux and Mac OS.  The
main reason for inquiring about plotting and such, is to create a set of
tools that would complement MacSpice(
http://home.earthlink.net/~wilsona/macspice.html) for plotting data and
producing presentation quality output.  Yes, I know I could use Matlab,
Igor Pro, IDL from Research Systems, Inc., or Excel( Arghh!!!), but I
wanted something that would be portable across platforms (MacOS,
Linux/Unix, Windows) as these are the machines I use most for my real
work: circuit simulation, and freely available.

It seems Snow, developed by David Ascher, is further along in
development for producing output and backend renderers. Thanks for the
pointer David( http://starship.python.net:9673/crew/da/Snow ).  I liked
the sample files.  They seem to be able to produce the multiple formats
that I am looking for with the multiple axis style.  I will try to set
this up on my Linux machine and test a few things.  If this works, I'll
look into setting it up on my Mac.  The big hurdle for the Mac will be
the use of PyPDF and PDFlib
(http://www.ifconnection.de/~tm/software/pdflib/index.html ) that is
used by Snow.  Any one planning/doing/done work in this area?? Let me

Questions on Snow:
1.  any comments on pursuing this for the Mac?  What do I need to set
everything up?  i.e. MacPython Source, PIL source, PDFlib source,
extension module setup, etc.
2.  Does Snow require PDFlib to produce GIF, JPEG, and PNG pictures or
is this supported by PIL?

Piddle, developed by Joe Strout ( http://www.strout.net/python/piddle/ )
is taking a different approach by making an independent graphics layer
that sits on top of the platform specific calls( i.e. backends ).  I
like this package because of the native calls and MacOS support.  Being
promoted as a package for producing 2-d graphics. With a plotting
package, Graphite, just getting started, this has potential also.  Also,
due to having native calls, it is mentioned that there may be some
capability for interaction by the user.  This would be a plus.  The
capability to annotate after the plot is rendered would be a big plus.
But there is only a Quickdraw backend available at the moment.  I'll try
this one after I look at Snow.

Question on Piddle:
1. Any time frame on the other backends?
2.  What are the requirements for Piddle?
3.  What does Piddle use to produce its PDF output?

Both packages have some, but not all (at the moment) of what I am
looking for.  It would be good to couple the two.  Use Piddle as the
generic graphics layer( for native on-Screen drawing ) and Snow as the
backend for producing the multiple output.  I doubt if this is possible
in a merged development effort.  But once Piddle is further along I plan
to look at more closely.

Thanks for reponses.
-anthony wilson