Hi I have a question about drawing a linear line in x, y plot. I usually use the following code, but for this time the x values are to small (-0.08 to -0.02) I wrote the following code, but r does not draw the line. However, it does not give an error when it takes the code. reg1<- lm(CWSI~NWI, data=Ahmed) NWI <- seq(-0.08, -0.02, len = -0.02) lines(NWI, predict(reg1, list(NWI NWI)),xlim=c(-0.08,-0.02),ylim=c(0,1),pch=1,col=1,lwd=2, lty=1) When I wrote the following code abline(reg1,pch=2,col=2,lwd=2, lty=2,xlim=c(-0.06,-0.02),ylim=c(0.3,0.8)) the line shows up, but I can not control the xlim or ylim. It bascally goes across the figure I appreciate your help -- Ahmed M. Attia Research Assistant Dept. Of Soil&Crop Sciences Texas A&M University ahmed.attia at ag.tamu.edu Cell phone: 001-979-248-5215
A few problems ... This statement doesn't make sense. seq(-0.08, -0.02, len = -0.02) Perhaps you meant seq(-0.08, -0.02, by = 0.02) The xlim= and ylim= are arguments to higher level plot functions, like plot(), and won't work for functions lines() or abline(). Are you trying to limit the range of the predicted line on the graph? If so, perhaps the following simple example will help. # randomly generate some fake data CWSI <- rnorm(20, sd=0.1) NWI <- rnorm(20, sd=0.1) # linear regression reg1 <- lm(CWSI~NWI) # show predicted line for small segment newNWI <- seq(-0.08, -0.02, by = 0.02) plot(NWI, CWSI) lines(newNWI, predict(reg1, list(NWI = newNWI))) Jean On Mon, Oct 28, 2013 at 10:30 AM, Ahmed Attia <ahmedatia80@gmail.com> wrote:> Hi > > I have a question about drawing a linear line in x, y plot. I usually > use the following code, but for this time the x values are to small > (-0.08 to -0.02) > > I wrote the following code, but r does not draw the line. However, it > does not give an error when it takes the code. > > > reg1<- lm(CWSI~NWI, data=Ahmed) > > NWI <- seq(-0.08, -0.02, len = -0.02) > lines(NWI, predict(reg1, list(NWI > NWI)),xlim=c(-0.08,-0.02),ylim=c(0,1),pch=1,col=1,lwd=2, lty=1) > > When I wrote the following code > > abline(reg1,pch=2,col=2,lwd=2, lty=2,xlim=c(-0.06,-0.02),ylim=c(0.3,0.8)) > > the line shows up, but I can not control the xlim or ylim. It bascally > goes across the figure > > I appreciate your help > -- > Ahmed M. Attia > > > Research Assistant > Dept. Of Soil&Crop Sciences > Texas A&M University > ahmed.attia@ag.tamu.edu > Cell phone: 001-979-248-5215 > > ______________________________________________ > 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. >[[alternative HTML version deleted]]
On Oct 28, 2013, at 8:30 AM, Ahmed Attia wrote:> Hi > > I have a question about drawing a linear line in x, y plot. I usually > use the following code, but for this time the x values are to small > (-0.08 to -0.02)That is not the problem.> > I wrote the following code, but r does not draw the line. However, it > does not give an error when it takes the code. > > > reg1<- lm(CWSI~NWI, data=Ahmed) > > NWI <- seq(-0.08, -0.02, len = -0.02)> seq(-0.08, -0.02, len = -0.02) integer(0) The length argument to seq doesn't make any sense. Please review: ?seq -- David> lines(NWI, predict(reg1, list(NWI > NWI)),xlim=c(-0.08,-0.02),ylim=c(0,1),pch=1,col=1,lwd=2, lty=1) > > When I wrote the following code > > abline(reg1,pch=2,col=2,lwd=2, > lty=2,xlim=c(-0.06,-0.02),ylim=c(0.3,0.8)) > > the line shows up, but I can not control the xlim or ylim. It bascally > goes across the figure > > I appreciate your help > -- > Ahmed M. Attia > > > Research Assistant > Dept. Of Soil&Crop Sciences > Texas A&M University > ahmed.attia at ag.tamu.edu > Cell phone: 001-979-248-5215 > > ______________________________________________ > R-help at 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.David Winsemius, MD Alameda, CA, USA
On 10/29/2013 02:30 AM, Ahmed Attia wrote:> Hi > > I have a question about drawing a linear line in x, y plot. I usually > use the following code, but for this time the x values are to small > (-0.08 to -0.02) > > I wrote the following code, but r does not draw the line. However, it > does not give an error when it takes the code. > > > reg1<- lm(CWSI~NWI, data=Ahmed) > > NWI<- seq(-0.08, -0.02, len = -0.02) > lines(NWI, predict(reg1, list(NWI > NWI)),xlim=c(-0.08,-0.02),ylim=c(0,1),pch=1,col=1,lwd=2, lty=1) > > When I wrote the following code > > abline(reg1,pch=2,col=2,lwd=2, lty=2,xlim=c(-0.06,-0.02),ylim=c(0.3,0.8)) > > the line shows up, but I can not control the xlim or ylim. It bascally > goes across the figure >Hi Ahmed, Have a look at ablineclip in the plotrix package. Jim