title: Gnuplot color gradients
body: <p>I need to create a number of vertical gradients in my plot - four in total, in order to clarify direction (N,E,S,W).</p>
  
  <pre><code>#set 0 to 45 degrees color
  set obj 1 rectangle behind from screen 0.09,0.2 to screen 0.89,0.29
  set palette model RGB defined ( 0 "white", 1 "red")  
  set cbrange[0:1]
  unset colorbox
  </code></pre>
  
  <p>Am I missing something here? 
  Thanks in advance</p>