title: Gnuplot contour plot without dots
body: <p>I am trying to plot a contour plot with labels with the following code.   </p>
  
  <pre><code>reset
  set terminal qt
  set pm3d map
  set contour base
  set cntrparam levels incremental 0, 10, 100
  set cntrlabel onecolor
  set palette rgbformulae 33,13,10
  
  # No key appears
  # splot 'temperature.dat' with pm3d title "Heated 2D plate"
  
  # Key appears
  splot 'temperature.dat' with pm3d, \
     'temperature.dat' with labels title "Heated 2D plate"
  </code></pre>
  
  <p>The outputs are shown below:</p>
  
  <p>No labels (first splot command) and without key
  <a href="https://i.stack.imgur.com/njkuA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/njkuA.png" alt="Heated 2D plate without labels"></a></p>
  
  <p>With labels and key (2nd splot command), but with dots.
  <a href="https://i.stack.imgur.com/nENXW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nENXW.png" alt="Heated 2D plate with labels"></a></p>
  
  <p>My questions:</p>
  
  <ol>
  <li>Why is the key not appearing in the first splot command?</li>
  <li>How to remove the dots when plotting with labels (2nd splot command)?</li>
  </ol>
  
  <p>Will attach the data file if required.</p>