title: X Y Plot with R
body: <p>I have this data</p>
  
  <pre><code>             X,           Y,      ag
     4068961.415,  731027.852,  1.5000
     4068962.701,  731027.829,  0.9500
     4068963.986,  731027.807,  2.5000
     4068965.271,  731027.784,  2.5000
     4068875.402,  730996.864,  3.9000
     4068875.402,  730996.864,  3.0796
     4068875.402,  730996.864,  1.6060
     4068910.645,  731067.069,  0.6400
  </code></pre>
  
  <p>Want a reproducible example ? copy this data and do  <code>d &lt;- read.csv("clipboard")</code></p>
  
  <p>How can I get a kind of map plotting the column named <code>ag</code>, depending on its coordinate ?</p>
  
  <p>I want</p>
  
  <ul>
  <li><code>X column</code> at the x axis</li>
  <li><code>Y column</code> at Y axis</li>
  <li>depending on <code>ag</code> value, the color of the plotted point changes (from yellow to red).</li>
  </ul>