title: Adding annotation (segment / arrow) in only certain facet ggplot
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/11889625/annotating-text-on-individual-facet-in-ggplot2">Annotating text on individual facet in ggplot2</a>  </p>
  </blockquote>
  
  
  
  <p>I am working on a data-set with 3 species. They are apple, orange and banana. </p>
  
  <p>I want to annotate the facets only on the bottom panel. However, by default I am getting annotations on all the plots. I was able to get text annotation only on the desired plot. However, I am confused what I need to do for the arrows / segments. </p>
  
  <p>Here is my code:</p>
  
  <pre><code>library(ggplot2)
  library(grid)
  
  tempobs &lt;- read.csv("temp data share.csv",header=T, sep=",")
  p1 &lt;- ggplot(tempobs,aes(x=time,y=data))+geom_point(data=tempobs,aes(x=time,y=data,colour=group1))+facet_wrap(~id,ncol=1)+theme_bw()
  p1 &lt;- p1 + xlab("Julian Day (2008-2009)")+ylab(expression(Temperature~(degree*C)))+ element_blank()+ theme(
      legend.position="right",
      legend.direction="vertical",
      legend.title = element_blank()) +coord_cartesian(xlim=c(250,550))+coord_cartesian(ylim=c(0,40))+scale_x_continuous(breaks=c(250,300,350,400,450,500,550),labels=c("250","300","350","34","84","134","184"))
  p1
  
  ### This is how it should look like (though shows annotations for all the plots)
  p + annotate("text",x=340,y=3,label="2008",size=3)+annotate("segment",x=366,xend=366,y=0,yend=2,size=0.5)+annotate("text",x=390,y=3,label="2009",size=3)+annotate("segment",x=366,xend=310,y=1,yend=1,size=0.5,arrow=arrow(length=unit(0.2,"cm")))+annotate("segment",x=366,xend=420,y=1,yend=1,size=0.5,arrow=arrow(length=unit(0.2,"cm")))
  
  
  ### This is what I did to show text annotation on the bottom panel
  ann_text &lt;- data.frame(x=c(340,390),y=c(3,3),id=c("orange"),label=c("2008","2009"))
  p1 &lt;- p1 + geom_text(data=ann_text,aes(x=x,y=y,label=label,size=3),show_guide=F)
  p1
  </code></pre>
  
  <p>Now, I want to add the arrows and segment based on the overall graph. </p>
  
  <p>My data can be found on <a href="https://www.dropbox.com/s/dfcmqrslskwdh80/temp%20data%20share.csv" rel="nofollow noreferrer">https://www.dropbox.com/s/dfcmqrslskwdh80/temp%20data%20share.csv</a></p>
  
  <p>My output is <img src="https://i.stack.imgur.com/dOuBO.png" alt="enter image description here"> </p>
  
  <p>This is what I got with only text annotation. But for segment annotation I always got error. You can notice text labels 2008 and 2009 added on the bottom panel. </p>
  
  <p><img src="https://i.stack.imgur.com/2sPYg.png" alt="enter image description here"></p>
  
  <p>The output shows the annotation I want but it is on all the facets. I want only on the bottom one. </p>
  
  <p>Thank you so much.</p>
  
  <p>Regards,
  Jdbaba</p>