title: Positions and text length of bar plot labels
body: <p>I am having trouble with some labels.  I am doing bar plots in r and I am a little shocked there isn't an easy command to just place the values at the top.  Anyway, I want these labels to be more centered in the bars and to shorten the significant digits so they will fit within the bar.  I would also appreciate any suggestions on how to streamline this.  </p>
  
  <p>I have tried options(digits=5) and this did not work for the labels.  I have used text(plot.name, tmp, labels= c(tmp) but wanted to try and not use this to make it simpler.  I have to remake a lot a plots.</p>
  
  <pre><code>tmp = c(mean(1.0000001:100),mean(100.0000001:200), mean(200.0000001:300), mean(300.0000001:400))
  
  barplot(tmp, names=c("site 1", "site 2", "site 3", "site 4") )
  
  text(1:4, tmp, label=tmp, pos=2, srt=90)
  </code></pre>