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.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.
>
> [[alternative HTML version deleted]]
>
> _______________________________________________
> R-SIG-Mac mailing list
> r-sig-...@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-mac
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