title: R - stat_contour() - Not possible to generate contour data
body: <p>I have approx. 4800 lat/lon points with a noise level, that I would like to draw contours on (e.g. 50dB, 55dB, ...). You can have a look at the data here: <a href="https://pastebin.com/LkfWYwJe" rel="nofollow noreferrer">https://pastebin.com/LkfWYwJe</a></p>
  
  <p>When I run</p>
  
  <pre><code>ggplot(
    data,
    aes(x =Lat, Lon, z = Value)
  ) + stat_contour(binwidth = 10)
  </code></pre>
  
  <p>I receive a</p>
  
  <pre><code>Warning message:
  Not possible to generate contour data 
  </code></pre>
  
  <p>Unfortunately I don't have any idea why this happens. Derived from other questions here, I tried less data, but this did not have an effect.</p>
  
  <p>Any hint/advice/remark is higly appreciated. Thanks!</p>
  
  <hr>
  
  <p><em>Edit:</em> The problem seems to be unrelated to data not building a grid. I uploaded new sample data, which forms a perfect grid. <a href="https://pastebin.com/F4c7hWcY" rel="nofollow noreferrer">https://pastebin.com/F4c7hWcY</a> This dataset shows the very same issue as described above.</p>