I have a set of Monte Carlo simulation results for a Quick Response Freight Model that I am currently preparing summary graphs. I want to show three things on the graphs; the model forecast, an approximate exponential best fit line, and a smooth line through mean+sd and mean-sd data points. As you can see I can get the first two, but all I can find when searching the help are references to fitting spline models to the data points. I'm old school, so I was used to using a french curve to draw the smooth lines I'm interested in. The problem is that I don't understand how/why of fitting a model to the data points. Here is an example of the data I am graphing: year mean sd 1 2010 6738 1721 2 2015 8793 2326 3 2020 11699 3333 4 2025 15951 5232 5 2030 22492 9768 6 2035 33289 24431 7 2040 52917 82341 And here is the R code I am currently using: gr = function (yr,rate,trk) trk*rate^(yr-2006) plot.results <- function(dfn) { dt <- read.table(dfn) res.g = nls(dt$mean ~ gr(dt$year, R, T), start=c(R=1.08, T=3700), data=dt) R <- as.numeric(coef(res.g)[1]) T <- as.numeric(coef(res.g)[2]) plot(dt$year,dt$mean, pch=1, col="green", main="Truck Forecast", xlab="Year", ylab="Truck Volume", ylim=c(0,max(dt$year+dt$sd))) curve(gr(x, R, T), add=TRUE, col="green") }
Any help is appreciated! Walter Anderson, GISP PBS&J 6504 Bridge Point Pkwy, Ste. 200 Austin, TX. 78730 P:512.342.3237 F:512.327.2453 M:512.364.8318 [[alternative HTML version deleted]] ______________________________________________ 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.