Thanks Jean, Your 1st solution was one I've tried, w/o great success. The 2nd works a lot better (on real, and more messy, data), especially when I set span to a much smaller number than 1/10. Thank you greatly. -Chuck
Jean V Adams wrote > Using the data you provided, a combination of slope and height comes > close: > > X <- seq(Y) > high <- Y > 0.6 > > upslope <- c(FALSE, diff(Y) > 0) > section <- rep(1, length(Y)) > section[upslope==TRUE & high==TRUE] <- 2 > section[upslope==FALSE & high==TRUE] <- 3 > plot(X, Y, col=section) > > > Or you could base the slope on the a smooth fit of the data rather than Y > itself: > > P <- loess(Y ~ X, degree=2, span=1/10)$fitted > > upslope <- c(FALSE, diff(P) > 0) > section <- rep(1, length(Y)) > section[upslope==TRUE & high==TRUE] <- 2 > section[upslope==FALSE & high==TRUE] <- 3 > plot(X, Y, col=section) > > Jean > > > > "chuck.01" < > CharlieTheBrown77@ > > wrote on 10/26/2012 03:14:29 AM: >> >> hello, >> I have some data that looks similar to this (only not as nice as this): >> >> Y <- c(abs(rnorm(100, 0.10, .1)), seq(.10, 1.0, .3)+rnorm(1, 0, .5) , >> seq(0.8, 4.0, .31)+rnorm(1, 0, .5) >> , seq(3.9, .20, -.2)+rnorm(1, 0, .5) , abs(rnorm(100, 0.13, .1)) , > seq(.10, >> 1.2, .35)+rnorm(1, 0, .5) >> , seq(0.7, 6.0, .31)+rnorm(1, 0, .5) , seq(5.9, .23, -.18)+rnorm(1, 0, > .5) , >> abs(rnorm(50, 0.18, .1)) ) >> >> plot(Y~c(1:length(Y))) # it is water level through time >> >> I am trying to find a way to divide these data into 3 sections , 1) the >> rising limbs, 2) falling limbs, and 3) not #1 or #2. >> I'll spare you the list of things I've tried, just know that the data is >> generally too noisy to use something as simple as which(diff(Y) > b), > where >> b is some threshold. >> Please let me know if you have an idea of how to tackle this. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@ > mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- View this message in context: http://r.789695.n4.nabble.com/deconstructing-curve-into-rising-and-falling-limbs-tp4647512p4647550.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
