R help - Aug 2013 - Adding additional points to ggplot2

Hi!
I am having a difficulty adding additional points to a plot using ggplot2..

The case is that I want to plot both original and estimated values in the
same graph, and general I would use 
plot and then lines, but I do not know how to do it with ggplot...

Thanks!

Regards,
Chris



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Hi Chris,

Just add a second geom_point() call and override the y axis mapping.
For example:

library(ggplot2)
ggplot(mtcars, aes(x=hp, y=mpg)) +
  geom_point() +
  geom_point(aes(y=qsec), color="red")

Best,
Ista

On Fri, Aug 16, 2013 at 5:45 AM, Chris89 <chrisege at stud.ntnu.no>
wrote:
> Hi!
> I am having a difficulty adding additional points to a plot using ggplot2..
>
> The case is that I want to plot both original and estimated values in the
> same graph, and general I would use
> plot and then lines, but I do not know how to do it with ggplot...
>
> Thanks!
>
> Regards,
> Chris
>
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Adding-additional-points-to-ggplot2-tp4673928.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.

Hi,

you could also use a factor variable to differentiate your observed and 
estimated values and change shape and/or color based on that factor. 

e.g.

ggplot(aes(x=X,y=Y, shape=factor(Type))) + geom_point()      #For changing 
shapes
ggplot(aes(x=X,y=Y, color=factor(Type))) + geom_point()        #For 
changing colors
ggplot(aes(x=X,y=Y, color=factor(Type), shape=factor(Type))) + 
geom_point()        #For changing colors

Ista also gave a good solution, but if you ever have more than two sets of 
points/lines to plot on the same graph you will have a simpler and faster 
way of doing it. Also, if your data is set into different columns and you 
do not have a factor, you can use the melt() function in the package 
reshape2.  Your data will be melted into one line with the value beside the 
variable i.e. the column name which can be used as a factor.


Cheers.

JM 

Le vendredi 16 ao?t 2013 05:45:21 UTC-4, Chris89 a ?crit
:
>
> Hi! 
> I am having a difficulty adding additional points to a plot using 
> ggplot2.. 
>
> The case is that I want to plot both original and estimated values in the 
> same graph, and general I would use 
> plot and then lines, but I do not know how to do it with ggplot... 
>
> Thanks! 
>
> Regards, 
> Chris 
>
>
>
> -- 
> View this message in context: 
>
http://r.789695.n4.nabble.com/Adding-additional-points-to-ggplot2-tp4673928.html
> Sent from the R help mailing list archive at Nabble.com. 
>
> ______________________________________________ 
> R-h... at r-project.org <javascript:> 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. 
>