# [SciPy-User] Spline Interpolation with non continuous data

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## [SciPy-User] Spline Interpolation with non continuous data

 Hi, I try to interpolated a spline throw a dataset (the record of a robot motion path). Usually it works really good, always when the robot drives without stops. But if the robot stops he moves a little bit backwards. If this happens I can’t use my “normal” method with the interpolate.UnivariateSpline-function(http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.UnivariateSpline.html), because the robot motion is not longer continuously. Does somebody has an idea which function could solve my problem? Or is there a good filter to reduce the redundant robot path. (the backwards path is only a little bit displaced relative to path without stops) Regards,     Franz_______________________________________________ SciPy-User mailing list [hidden email] http://mail.scipy.org/mailman/listinfo/scipy-user
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## Re: Spline Interpolation with non continuous data

 Hello, pchip sometimes does wonders ("wonders"=="oscillation-free") on data with piecewise continuous derivatives. Spline fits of degree 1 should also work. OTOH, sometimes pchip makes little difference from regular cubic splines, and in those cases the filtering may be your only option import scipy.interpolate from numpy import linspace xdata = ... ydata = ... f_approx = scipy.interpolate.pchip(xdata,ydata) ####Now that you have continuous function, use it many ways, ###   for example: xeval = linspace(x_low, x_high, 201) #set evaluation points yeval = f_approx(xeval) Cheers, Eric On 6/22/2013 9:14 AM, Franz Engel wrote: > Hi, > > I try to interpolated a spline throw a dataset (the record of a robot > motion path). Usually it works really good, always when the robot drives > without stops. But if the robot stops he moves a little bit backwards. > If this happens I can’t use my “normal” method with the > interpolate.UnivariateSpline-function(http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.UnivariateSpline.html), > because the robot motion is not longer continuously. Does somebody has > an idea which function could solve my problem? Or is there a good filter > to reduce the redundant robot path. (the backwards path is only a little > bit displaced relative to path without stops) > > Regards, > >       Franz > > > > _______________________________________________ > SciPy-User mailing list > [hidden email] > http://mail.scipy.org/mailman/listinfo/scipy-user> _______________________________________________ SciPy-User mailing list [hidden email] http://mail.scipy.org/mailman/listinfo/scipy-user