How to average plots that differ in x and y data?
11 views (last 30 days)
Show older comments
Hello- I currently have three different datasets that signify results of heating up 3 different specimens. Since they were carried in different times, they vary in time and value, but also differ in the number of datapoints it used.
I am trying to plot the average of the three.
Now if the number of datapoints are the same, the method is quite simple- but my case is something like:
dataset a: 2 x 10 dataset dataset b: 2 x 15 dataset dataset c: 2 x 20 dataset
but imagine they signify a temperature rise. This also starts and ends in different values.
Doing some research I also found a exchange based program called plotaverage, but it is a bit confusing for me to find out how to use it, and the example I saw of it being used was for datasets that contained the same amounts of data.
Any help will be greatly appreciated!
thank you s
1 Comment
Star Strider
on 27 Apr 2017
It would help to have some or all of your data, or data similar enough to it to be relevant (as a ‘.mat’ file attached here) and a bit better description of what you want to do with it.
Is interpolation an option to create equal-length vectors if that is necessary?
Answers (1)
Joseph Cheng
on 28 Apr 2017
you can do something like
x1 = 0:.01:4;
x2 = 0:.03:5;
x3 = 0:.02:6;
y1 = sin(3*pi*x1);
y2 = sin(3*pi*x2);
y3 = sin(3*pi*x3);
figure,plot(x1,y1,'o',x2,y2,'s',x3,y3,'x')
p(1)=pchip(x1,y1);
p(2)=pchip(x2,y2);
p(3)=pchip(x3,y3);
time = min([x1 x2 x3]):...
min([diff(x1) diff(x2) diff(x3)]):...
max([x1 x2 x3]);
for ind = 1:3
output(ind,:)=ppval(p(ind),time);
end
% cut out unkown time
output(1,find(time>max(x1)))=nan;
output(2,find(time>max(x2)))=nan;
output(3,find(time>max(x3)))=nan;
hold on
plot(time,output',time,nanmean(output),'--')
legend('data1','data2','data3',...
'interp1','interp2','interp3',...
'average sig')
which you'll end up with the interpolation using pchip(), you can take a look at spline() depending on how you want to interpolate. with the set code you can code in to set the interpolated time to the shortest time, or what i show above by setting the interpolated section beyond the known with Nan's for each signal and then use nanmean() to not average them
0 Comments
See Also
Categories
Find more on Interpolation in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!