title: gnuplot: plotting single palette in multiplot mode
body: <p>I would like to ask some help on the following topic:</p>
  
  <p>The following code produces 3 plots (3 rows, 1 column) on the same page:</p>
  
  <pre><code>set terminal postscript color
  set output "test.ps"
  file="test.dat"
  
  set palette rgb 33,13,10  
  set cblabel "[km]"
  set cbtics 2.5, 5, 20 format "%.0f"
  
  set lmargin at screen 0.08
  set rmargin at screen 0.88
  # BUILD FROM BOTTOM TO TOP #
  TOP=0.92  #
  DY = 0.27 # DIMENSION OF Y
  
  set multiplot
  set grid
  set offset 0, 0, graph 0.05, graph 0.05 
  
  #unset colorbox
  # BOTTOM GRAPH #
  set xlabel "Second of the Week [s]"
  set ylabel "Up [m]" offset 1.5
  set ytics -0.7, 0.2, 0.4
  set yrange[-0.75:0.35]
  set tmargin at screen TOP-2*DY
  set bmargin at screen TOP-3*DY
  plot file u 1:12:3 notitle palette 
  # MIDDLE GRAPH #
  set xtics format ''
  unset xlabel 
  set ytics -0.3, 0.2, 0.8
  set yrange[-0.35:0.75]
  set ylabel "North [m]"
  set tmargin at screen TOP-DY
  set bmargin at screen TOP-2*DY
  plot file u 1:11:3 notitle palette
  # TOP GRAPH #
  set title "test"
  set ylabel "East [m]"
  set ytics -0.7, 0.2, 0.4
  set yrange[-0.9:0.25]
  set tmargin at screen TOP
  set bmargin at screen TOP-DY
  plot file u 1:10:3 notitle palette
  
  unset multiplot
  </code></pre>
  
  <p>The above code produces the following plot: </p>
  
  <p><img src="https://i.stack.imgur.com/C75bs.png" alt="color coded measurements"></p>
  
  <p>In the plots, the data are shown according to the distance from an origin. The distance is color coded and the palette used is plotted on the right of each graph.</p>
  
  <p>My question would be:
  - how do I obtain the same graph but with a single vertical palette on the right of the 3 plots? I want a single palette to be shown from the top of the first graph (East) to the bottom of the third graph (Up). This would allow me to enlarge the palette as well and would result in a cleaner plot.</p>
  
  <p>Any help is greatly appreciated. </p>