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" <[EMAIL PROTECTED]> Newsgroups: comp.lang.python To: <python-list@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" <[EMAIL PROTECTED]> 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 > > > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
