[R] Fit a smooth closed shape through 4 points

Alexander Shenkin ashenkin at ufl.edu
Mon Mar 21 13:59:46 CET 2016

Hello all,

I have sets of 4 x/y points through which I would like to fit closed, 
smoothed shapes that go through those 4 points exactly.  smooth.spline 
doesn't like my data, since there are only 3 unique x points, and even 
then, i'm not sure smooth.spline likes making closed shapes.

Might anyone else have suggestions for fitting algorithms I could employ?


shapepoints = structure(c(8.9, 0, -7.7, 0, 0, 2, 0, 3.8), .Dim = c(4L,
2L), .Dimnames = list(NULL, c("x", "y")))


# repeat the first point to close the shape
shapepoints = rbind(shapepoints, shapepoints[1,])


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