How to make animations with Gnuplot

This is how you do it:

set terminal gif animate delay 10

The delay 10 means 10*0.01 seconds between each image. Then, you just plot each subsequent image until your done. I normally write a bash script to do this sort of thing automatically, so here’s an example.


#!/bin/bash
MAX=100
echo "clear" > plot.gpi
echo "reset" >> plot.gpi
echo "set terminal gif animate delay 10" >> plot.gpi
echo "set output \"animate.gif\"" >> plot.gpi
echo "set isosample 40" >> plot.gpi
echo "set hidden3d" >> plot.gpi
for i in `seq 0 ${MAX}`
do
echo "splot sin(${i}*x/${MAX})*cos(${i}*y/${MAX})" \
>> plot.gpi
done


So what I’m doing here is letting a bash script create a gnuplot script for me. Instead of writing out about a hundred different splots by hand, I let a for loop do that for me. Additionally, I specify a few things at the beginning.
So, put that code in a file somwhere.
Make it executable:chmod +x file
Then run it: ./file
Now, you should have a file plot.gpi that contains all the gnuplot commands.
Now open gnuplot: gnuplot
Then run the plot.gpi script: gnuplot> load 'plot.gpi'
And now you should have an animated gif creatively titled animation.gif.

When I do this in real life, I normally have a data file (perhaps generated with octave/matlab) with each time step separated by two blank lines. After two blank lines, gnuplot says we are on a new index so I can make my repeated plot line as something like:
for i ...; do echo "plot 'datafile' using 1:2 index ${i} with lines"; done etc…

Tags: bash, gnuplot, linux