Curve quantification I have some longitudinal measurement data of 15,000. I smoothed that data with B-spline smoothing and got the following curve.

I then want to quantify this curve and extract features for clustering the curve of 15,000 data.
So I will calculate the curvature to quantify the curve and add that curvature to the features. To increase the number of features for clustering, I would like to obtain features by other means of quantification. However, I do not know of any other means of quantifying curves. So, please tell me other ways to quantify the curve.

One could put all the curves together and apply FPCA. As the underlying data are "dense" we can use the FPCA projection scores directly (e.g. for clustering as in the OPs request) and interpret their respective modes of variation.
