[R] How to fit a line through the "Mountain crest", i.e., through the highest density of points - in a "loess-like" fashion.
dwinsemius at comcast.net
Sun Mar 11 01:46:03 CET 2012
On Mar 10, 2012, at 3:55 PM, Emmanuel Levy wrote:
> I'm trying to normalize data by fitting a line through the highest
> of points (in a 2D plot).
> In other words, if you visualize the data as a density plot, the fit
> trying to achieve is the line that goes through the "crest" of the
Are you familiar with the kde2d of bkde2D functions in various
packages? If you then collected the max density for each X and Y you
might want to see whether that 2-d function would follow a
sufficiently regular path that would represent the projection of the
ridge on the z=0 plane.
> This is similar yet different to what LOESS does.
Do you want a curve or a line?
> I've been using loess
> before, but it does not exactly that as it takes into account all
> Although points farther from the fit have a smaller weight, they
> result in
> the fit being a bit off the crest.
> Do you know a package or maybe even an option in loess that would
> allow me
> achieve this?
I don't. I happen to have a dataset where I could test it. But you are
likely to get better responses if you provide a test case.
> Any advice or idea appreciated.
> [[alternative HTML version deleted]]
Plain text is preferred.
David Winsemius, MD
West Hartford, CT
More information about the R-help