[download] Hello, I have a set of (x,y) points (shown in the attached dpng) which I would like to create a smoothing spline through. Normally, I don’t have a problem doing a fit like this using Spline1D() from Dierckx.jl or interpolate() from BSplineKit.jl. The difficulty I have with this particul…

My guess is that you have sorted the point on the x-coordinate ? If you have the points in their “natural” order, I think a parametric analysis could do the trick (fit x(s) and y(s) interdependently and then plot the result). An example where I tried to sort the points to get a “natural order” is in…

[image] hanshinlee77: Hello, I have a set of (x,y) points (shown in the attached dpng) which I would like to create a smoothing spline through. Many of these methods (e.g. Dierckx) require you to supply a parameterization (t_i,x_i,y_i) of your points. If your points are roughly “in order”, t…

Interesting problem. I’m thinking create a 2D log density function and maximize the log-likelihood of the points. Then create a spline/approxfun or similar and maximize the integral of the above log-likelihood along the contour.

Thank you all for chiming in on this problem. I ended up ditching spline fit and fitting a generalized gaussian function with a skew angle to the data points to get a reasonable fit. The plot below is upside down compared to the original plot. The fit parameters were center, width, depth, \gamma (pr…

[image] hanshinlee77: tracing the peaks of that histogram (or density map) to build a 2D curve which I then spline fit. I am guessing that this might be similar to what @dlakelan suggested. That’s very similar to what I suggested, except my suggestion basically generalized that a bit. Since …

Yes, it was indeed a tricky problem I encountered while thinking about this: how to measure the distance (as a merit of a fit) from a spline curve to those points. Your density function approach makes sense and is the one I will be trying. Appreciate it!

Smoothing spline fit through a set of (x,y) points

General Usage

rafael.guerra October 12, 2023, 6:06am 3

Please give it a try to Dierckx’s smooth parametric splines. See this example.

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Smoothing spline fit through a set of (x,y) points

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