title: R - Multiple compasses in tmap
body: <p>Is it possible to include more than one <code>tm_compass()</code> on a map created by <code>tmap</code>?</p>
  <p>I know it's probably unlikely that you'd need to, but say you wanted to show off the different compass types. Using <code>nz</code> from the <code>spData</code> package I tried adding each new compass as an additional layer, but it seems only the first one is included on the map.</p>
  <pre><code>library(spData)
  library(tmap)
  
  tm_shape(nz)+
    tm_fill()+
    tm_compass(type = 'arrow', position = c(0.1, 0.9))+
    tm_compass(type = '4star', position = c(0.1, 0.8))+
    tm_compass(type = '8star', position = c(0.1, 0.7))+
    tm_compass(type = 'radar', position = c(0.1, 0.6))+
    tm_compass(type = 'rose', position = c(0.1, 0.5))
  </code></pre>
  <p><a href="https://i.stack.imgur.com/19Fg9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/19Fg9.png" alt="enter image description here" /></a></p>
  <p>If <code>arrow</code> isn't included, then <code>4star</code> takes it's place:</p>
  <pre><code>tm_shape(nz)+
    tm_fill()+
    # tm_compass(type = 'arrow', position = c(0.1, 0.9))+
    tm_compass(type = '4star', position = c(0.1, 0.8))+
    tm_compass(type = '8star', position = c(0.1, 0.7))+
    tm_compass(type = 'radar', position = c(0.1, 0.6))+
    tm_compass(type = 'rose', position = c(0.1, 0.5))
  </code></pre>
  <p><a href="https://i.stack.imgur.com/ZGFdE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZGFdE.png" alt="enter image description here" /></a></p>