Spline interpolation with R
14,091
Why not using splinefun
:
func = splinefun(x=x, y=population, method="fmm", ties = mean)
Then you define the point to forecast you want:
func(seq(1973, 2014, 0.25))
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Author by
Gilles Cosyn
Updated on October 21, 2022Comments
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Gilles Cosyn over 1 year
I want to perform a (cubic) spline interpolation for population data to "transform" yearly data into quarterly data. I know that there are a fair number of flaws doing so, but I need to do it.
Here is an example of my code (using generic input data):
#--------------spline interpolation x = c(1973:2014) population = seq(500000, 600000, length.out = 42) list = spline(x, population, n = 4*length(x), method = "fmm", xmin = min(x), xmax = max(x), ties = mean) x_spline = list$x pop_spline = list$y
How can I define that the splines are calculated "quarterly", in other words at 1973.25, 1973.5, 1973.75, 1974 etc.? Sorry for not being an expert in statistics: What would be the best method to "transform" yearly data into quarterly data: "fmm", "natural", "periodic", "monoH.FC" or "hyman"? The assumption would be that the growth of population is evenly distributed over the year.
Best regards and many thanks in advance!
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Gilles Cosyn over 9 yearsVery neat solution! Thanks a lot! :)
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Colonel Beauvel over 9 yearsNo problem! Always better to have a function than a vector since you can evaluate the first on a different vector !
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Gilles Cosyn over 9 yearsGood to know! Sounds reasonable.