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List:       r-sig-mac
Subject:    Re: [R-SIG-Mac] [R] plot 2 graphs on the same x-y plane
From:       Susan Gruber <sgruber () hsph ! harvard ! edu>
Date:       2012-04-11 13:42:20
Message-ID: 7C095DDC-9580-4208-BF76-1D974C886AFE () hsph ! harvard ! edu
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Hi,
A line can be added to an existing plot using the abline function.  For example, if a \
is the intercept and b is the slope, the command would be  abline(a=a, b=b)

To overlay a new plot on an existing one, use the command: par(new=TRUE).  
For example:

plot(1:10, 1:10)
par(new=TRUE)
plot(log(1:10), 1:10)

This approach often leads to issues with the scale of the axes, tick marks, and \
labels.  Fortunately, R provides the flexibility to deal with all of them. I \
recommend you carefully read the help pages for plot, par, and axis, and have some \
fun playing around with all the options.

--Susan


On Apr 10, 2012, at 11:55 PM, Tawee Laoitichote wrote:

> 
> 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. !
 Ta!
> 
> wee Mac OS10.7.3
> > From: michael.weylandt@gmail.com
> > Date: Tue, 10 Apr 2012 23:31:08 -0400
> > Subject: Re: [R] plot 2 graphs on the same x-y plane
> > To: ohowow2007@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
> > <ohowow2007@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.
> 		 	   		  
> 	[[alternative HTML version deleted]]
> 
> _______________________________________________
> R-SIG-Mac mailing list
> R-SIG-Mac@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-mac

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