You were told before this isn't a Mac question so please don't cc R-SIG-Mac.
I'm not sure what this bit of your reply means "My question is to find any command to plot the data I got from the field;" but your reply later suggests that your problem is that you are overriding previous plots on a given device. By default, plot() does this -- if you want to add elements, you need to use points() or lines() (or some function that calls those, like abline() as I demonstrated) E.g., # Removes first plot plot(1:20) plot(0:19, col = 2) # Adds to plot plot(1:20) points(0:19, col = 2) Michael 2012/4/10 Tawee Laoitichote <ohowow2...@hotmail.com>: > Dear Michael (and Davis), > > Your answer is not what I want to know. My question is to find any command > to plot the data I got from the field; such as a set of (x,y) data ( I > actually have these data) and together withe the derived ones . I brought > these data to plot on x-y plane, getting a graph showing some > relation. Then, I wanted to find some linear relation, I would use least > square method to solve having a simple function such as; y = ax + b, solving > the a and b. So, I could plot a straight line using this function, or > perhaps forecast some data of y which I know the value x. > > My problem is when I did a scatter plot by command "plot(x,y)", I got a > graph. Whilst I plotted another graph using the above function the existing > graph disappeared replaced be the latter function. > > Unfortunately, after searching a while to find the solution command, I can > not find the command. I asked the question as to request some help not the > example you shown. > > Any way, thanks for you effort. > > Tawee > > Mac OS10.7.3 > >> From: michael.weyla...@gmail.com >> Date: Tue, 10 Apr 2012 23:31:08 -0400 >> Subject: Re: [R] plot 2 graphs on the same x-y plane >> To: ohowow2...@hotmail.com >> CC: r-help@r-project.org >> >> This is the same malformatted message you posted on R-SIG-Mac even >> after David specifically asked for clarification.... not to reward bad >> behavior, but perhaps this will enlighten: >> >> # Minimal reproducible data! >> x <- runif(15, 0, 5) >> y <- 3*x - 2 + runif(15) >> >> dat <- data.frame(x = x, y = y) >> rm(list = c("x", "y")) >> >> # Base graphics plot using the formula interface >> plot(y ~ x, data = dat) >> abline(lm(y~x, data = dat), col = "red3", lwd = 2) >> >> Alternatively >> >> library(ggplot2) >> ggplot(dat, aes(x = x, y = y)) + geom_point() + stat_smooth(method = >> "lm", color = I("red3")) >> >> which is perhaps overkill in this situation. >> >> >> Michael >> >> On Tue, Apr 10, 2012 at 11:03 PM, Tawee Laoitichote >> <ohowow2...@hotmail.com> wrote: >> > >> > >> > >> > >> > hi, I'm doing some data on least square curve fitting. What I like to >> > have is to compare the scatter plot whilst having the fitting curve on the >> > same coordinates. Any suggestting command besides plot(x,y). TaweeMac OSX >> > 10.7.3 >> > [[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. ______________________________________________ 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.