[R] using png and identify commands

[Antonio Silva]

Thanks Henrik and Tom, job done. Nice solutions.

All the best

Antonio Olinto

2015-02-02 17:31 GMT-02:00 Henrik Bengtsson <hb em biostat.ucsf.edu>:

> On Mon, Feb 2, 2015 at 9:56 AM, Antonio Silva <aolinto.lst em gmail.com>
> wrote:
> > Hi R users
> >
> > I want to save a plot after using the command identify.
> >
> > I use identify to place labels manually near the points in order to avoid
> > overlapping lines and numbers.
> >
> > x<-c(1,2,3,4,5,6)
> > y<-c(20,30,15,7,25,40)
> > plot(x,y,type="b",ylim=c(0,45))
> > identify(x,y,labels=y)
> >
> > But when I add
> >
> > png(filename="test.png",width=20,height=20,units="cm",res=300)
> > x<-c(1,2,3,4,5,6)
> > y<-c(20,30,15,7,25,40)
> > plot(x,y,type="b",ylim=c(0,45))
> > identify(x,y,labels=y)
> > dev.off()
> >
> > The plot is saved directly, without the identification of the points.My
> > question is: how to save the plot only after having labelled the points.
>
> Not that surprising, because identify() needs an "interactive" /
> screen device, e.g. From help("identify"): "identify is only supported
> on screen devices such as X11, windows and quartz. On other devices
> the call will do nothing."
>
> You need to do it in two steps, e.g.
>
> x<-c(1,2,3,4,5,6)
> y<-c(20,30,15,7,25,40)
> plot(x,y,type="b",ylim=c(0,45))
> marks <- identify(x,y,labels=y,pos=TRUE)
>
> png(filename="test.png",width=20,height=20,units="cm",res=300)
> plot(x,y,type="b",ylim=c(0,45))
> xym <- cbind(x=x[marks$ind], y=y[marks$ind])
> points(xym)
> text(xym, labels=xym[,"y"], pos=marks$pos)
> dev.off()
>
>
> To make sure you call the exact same plot commands in the two steps,
> you can also do:
>
> library("R.devices")
>
> x<-c(1,2,3,4,5,6)
> y<-c(20,30,15,7,25,40)
>
> marks <- NULL
> devEval(c("x11", "png"), name="test", {
>   plot(x,y,type="b",ylim=c(0,45))
>   if (is.null(marks)) {
>     marks <- identify(x,y,labels=y,pos=TRUE)
>   } else {
>     xym <- cbind(x=x[marks$ind], y=y[marks$ind])
>     points(xym)
>     text(xym, labels=xym[,"y"], pos=marks$pos)
>   }
> })
>
> /Henrik
>
> >
> > I use R integrated to gedit in UBUNTU Trusty Tahr 64 bits. I'd like to
> save
> > the plot using command lines and not GUIs
> >
> > Thanks for any help. Best regards,
> >
> > Antonio Olinto
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> > 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.
>



-- 
Antônio Olinto Ávila da Silva
Biólogo / Oceanógrafo
Instituto de Pesca (Fisheries Institute)
São Paulo, Brasil

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