Another approach would be to use ggplot2. Code can look a bit daunting to begin with but ggplot2 is a very versitile graphing package and well worth learning.
Simple example ============================================================= library(ggplot2) mydata <- data.frame(site=c("A","A","A", "B","B","B"), time1 = 1:6, t1=c(23,24,13,7,19,12), t2=c(7, 4,6,8,5,9)) p <- ggplot(mydata, aes(x=time1)) + geom_point(aes(y= t1, colour= site)) + geom_point(aes(y = t2, colour=site)) p <- ggplot(mydata, aes(x=time1)) + geom_point(aes(y= t1, colour= site)) + geom_point(aes(y = t2, colour=site)) p <- p + scale_x_continuous('Time')+ scale_y_continuous('Temperature') p ============================================================= --- On Mon, 11/21/11, SarahH <sarah....@hotmail.co.uk> wrote: > From: SarahH <sarah....@hotmail.co.uk> > Subject: [R] Scatter plot - using colour to group points? > To: r-help@r-project.org > Received: Monday, November 21, 2011, 2:17 PM > Dear All, > > I am very new to R - trying to teach myself it for some MSc > coursework. > > I am plotting temperature data for two different sites over > the same time > period which I have downloaded from a university weather > station data > archive. > > I am using the following code to create the plot > > plot ( x = TEMP3[,"TIME"], y = TEMP3[,"TEMP"], type = "p", > col = > TEMP3[,"SITE"], pch = 3, main = "Temperature changes", xlab > = "Date", ylab = > "Temberature[C]") > > I managed to use col = TEMP3["SITE"] to plot the two > different sites( BG1 > and EA7) in different colours, but I am struggling to > change the colours. > > I wanted to up a colour scheme to match the site, so tried > > > BG1 <- "blue" > EA7 <- "green" > > before the plot function, but the graphic just came out > with red and black > as before. > > There are other datasets in which there are more than two > sites so I would > really like to learn how to use colour to distinguish > between them on a > plot. > > Any direction would be very greatly received! > > Thank you very much > > Sarah > > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Scatter-plot-using-colour-to-group-points-tp4092794p4092794.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. > ______________________________________________ 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.