Question

I have two graphs, one is measurement (graph2), and one is result from the simulation (graph1). I need to plot them on one figure in Matlab but the problem is that graph1 has samples and graph2 has time value assigned to x-axis. How to make time from samples or samples from time to plot them on the same graph ?

This above picture is Graph1 and below is Graph2.

The time when they reach 0 is for:

graph1: x=3444

graph2: x=259

Answer 1

I think your problem is that one plot uses the indices to the samples as its x-values, wheras the other uses actual times as x-values.

You’ll have to scale the x-axis to have both x-axes describe to the same quantity. I don’t know the specifics of how you take samples, but here’s a simple example:

figure(1), clf, hold on

% some example data
x1 = 0:0.1:2*pi;  
y1 = sin(x1);    

x2 = 0:numel(x1);    % add a bit of noise, just for kicks
y2 = sin(2*pi*x2/numel(x1)) + 0.02*randn(size(x2));    

% plot naively
subplot(1,2,1), hold on
plot(x1, y1, 'r')
plot(x2, y2, 'b')    

% plot w/ re-scaled x-axis
subplot(1,2,2), hold on
plot(x1, y1, 'r')

x2 = linspace(min(x2(:)), max(x1(:)), numel(x2));

plot(x2, y2, 'b')

Output:

Again, the specific implementation of how you should re-scale your x-data depends on specifics of your experiment. You’ll probably have to tinker a bit to get them to correspond.