Plotting two axes in gnuplot

axesgnuplotplot

Is it possible to plot two curves, with two corresponding axes in gnuplot, each of which has a different scale?

For example, y=x**2 and y=x**4 in the same graph (they vary enough to be "uncomfortable" when plotted with the same scale).

Best Answer

You can have the axes handled automatically without you having to scale them yourself and keep auto-scaling:

set terminal jpeg
set output 'graph.jpg'

set xrange [-10:10]
set ytics 10 nomirror tc lt 1
set ylabel '2*x' tc lt 1
set y2tics 20 nomirror tc lt 2
set y2label '4*x' tc lt 2
plot 2*x linetype 1, 4*x linetype 2 axes x1y2

Related Solutions

R – Plot two graphs in same plot in R

lines() or points() will add to the existing graph, but will not create a new window. So you'd need to do

plot(x,y1,type="l",col="red")
lines(x,y2,col="green")

R – How to plot two histograms together in R

Here is an even simpler solution using base graphics and alpha-blending (which does not work on all graphics devices):

set.seed(42)
p1 <- hist(rnorm(500,4))                     # centered at 4
p2 <- hist(rnorm(500,6))                     # centered at 6
plot( p1, col=rgb(0,0,1,1/4), xlim=c(0,10))  # first histogram
plot( p2, col=rgb(1,0,0,1/4), xlim=c(0,10), add=T)  # second

The key is that the colours are semi-transparent.

Edit, more than two years later: As this just got an upvote, I figure I may as well add a visual of what the code produces as alpha-blending is so darn useful:

enter image description here

Best Answer

Related Solutions

R – Plot two graphs in same plot in R

R – How to plot two histograms together in R

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