title: Plotting points on a map with colors depending on their value, using coordinates
body: <p>I am new to R and trying to plot some points in different colors on a map, concerning their values and using coordinates.
  Data (df) looks as follow:</p>
  
  <blockquote>
    <p>longitude latitude value</p>
    
    <p>-9.41667 
    147.5333
    0.32</p>
    
    <p>-9.41667
    147.5333
    0.56</p>
    
    <p>-9.33333
    147.2333
    0.78</p>
    
    <p>-19.23948
    146.8044
    0.53</p>
    
    <p>-35.26409
    149.0835
    0.49</p>
    
    <p>-24.79456
    147.7503
    0.74</p>
    
    <p>-27.49773
    152.7428
    0.73</p>
  </blockquote>
  
  <p>I used <code>ggmap::get_map</code>:</p>
  
  <pre><code>MAP &lt;- get_map(location='australia', zoom=4, maptype = "terrain", source='google', color='color')
  </code></pre>
  
  <p>and then tried the following: </p>
  
  <pre><code>ggmap(MAP) + geom_point(data = df , aes(x=longitude, y=latitude, color= value))
  </code></pre>
  
  <p>It is only plotting the values, but how can I plot the values in different colors on the map I got? </p>