Data smoothing algorithms? - Thank you all

[Anthra Norell]

Thank you all for your solutions! The moving average filter will surely do.
I will take a closer look at SciPy, though. The doc is impressive. I believe
it's curve fitting I am looking for rather than interpolation. There's a
chapter on that too.

Frederic


----- Original Message -----
From: "Larry Bates" <lbates at syscononline.com>
Newsgroups: comp.lang.python
To: <python-list at python.org>
Sent: Friday, April 29, 2005 9:02 PM
Subject: Re: Data smoothing algorithms?


> Sounds like what you are looking for is spline interpolation.
> Given a set of datapoints is passes spline curves through
> each point giving you smooth transitions.  Did a lot of this
> in Fortran MANY years ago.
>
> Google turned up:
>
> http://www.scipy.org/documentation/apidocs/scipy/scipy.interpolate.html
>
> http://cmp.felk.cvut.cz/~kybic/thesis/pydoc/bigsplines.html
>
> http://www.mirror5.com/software/plotutils/plotutils.html
>
> Good Luck
> Larry Bates
>
> John J. Lee wrote:
> > "Anthra Norell" <anthra.norell at tiscalinet.ch> writes:
> >
> >
> >>Hi,
> >>
> >>The following are differences of solar declinations from one day to
> >>the next, (never mind the unit). Considering the inertia of a
> >>planet, any progress of (apparent) celestial motion over regular
> >>time intervals has to be highly regular too, meaning that a plot
> >>cannot be jagged. The data I googled out of Her Majesty's Nautical
> >>Almanac are merely nautical precision and that, I suppose, is where
> >>the jitter comes in. There's got to be algorithms out there to iron
> >>it out. If it were a straight line, I could do it. But this, over
> >>the whole year, is a wavy curve, somthing with a dominant sine
> >>component. Suggestions welcome.
> >
> >
> > The important thing is to have a (mathematical, hopefully) model of
> > how you expect the data to vary with time.  Start from there, and
> > then, for example, use regression to fit a curve to the data.
> >
> > The "Numerical Recipes" (Press et al.) book is popular and IMHO is a
> > good place to learn about these things (comes in several language
> > flavours, including Fortran and C -- sadly no Python AFAIK), though
> > the implementations aren't a great choice for serious "production"
> > use, according to those in the know.
> >
> > OTOH, there are quick and dirty methods that don't involve any model
> > worth speaking of -- and Press et al. covers those too :-)
> >
> >
> > John
> >
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