title: Reverse colors from ggmap points
body: <p>I want to reverse the color of the points and the label from the following ggmap creation:</p>
  <pre><code>ggmap(Map) +
    geom_point(data = DF, aes (x = Longitude, 
                                  y = Latitude, 
                                  color = RPM)) +
    labs(y = &quot;Latitude&quot;, x = &quot;Longitude&quot;, color = &quot;RPM&quot;)
  </code></pre>
  <p>I wouldn't like to change by now the data set to spatial points.</p>
  <p>I'm getting the following result:</p>
  <p><a href="https://i.stack.imgur.com/KLJuF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KLJuF.png" alt="Map" /></a></p>
  <p>I have tried the following addition to the code presented:</p>
  <pre><code>scale_colour_brewer(direction = -1)
  </code></pre>
  <p>But I'm getting the following error message:</p>
  <p><em>Error: Continuous value supplied to discrete scale</em></p>