title: big dotted geom_line, but dots closer together
body: <p>I am curious if it is possible to increase the size of dots on a dotted line within geom_line but keep the dots closer together. The R code below produces a basic reproducible example of what I see, and then I include another chart showing what I would like to see.</p>
  
  <pre><code>library(dplyr)
  library(ggplot2)
  set.seed(5223)
  myDF &lt;- data.frame(x=rnorm(20,0,1),
                     y=runif(20,0,20))
  myDF &lt;- myDF %&gt;% 
    mutate(From8to12 = y&gt;=8 &amp; y&lt;=12)
  
  ggplot(myDF,aes(x=x,y=y,col=From8to12)) +
    geom_point() +
    geom_hline(yintercept=8,lty="dotted") +
    geom_hline(yintercept=12,lty="dotted",size=1.5)
  </code></pre>
  
  <h1>Unedited Image</h1>
  
  <p><a href="https://i.stack.imgur.com/HMJNR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HMJNR.png" alt="Unedited image"></a></p>
  
  <h1>(Manually) Edited Image (In Paint)</h1>
  
  <p>I would like to make the dots bigger, but closer together. Is this possible? I've found nothing online.</p>
  
  <p><a href="https://i.stack.imgur.com/ZDXYx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZDXYx.png" alt="Edited Image"></a></p>