How to graph the outline of a curve

Hello.

I'm trying to plot (x,T) and want to just depict the upper limit curve. I tried to use other Matlab programs others have posted and the findpeaks equation, but I'm not getting much luck.

I want to plot this curve instead of filtering the data and distorting it in a way. Could anyone help me out please? Thank you for your time!

Answer 1

[Mohammad Abouali]

How does this work for you?

load Example
[pks,locs]=findpeaks(T,x,'MinPeakDistance',3);
plot(x,T);
hold on
plot(locs,pks,'r','LineWidth',3)

The redline is the upper bound.

[dj]

It tells me the following: Error using findpeaks>parse_inputs (line 131) Expected a string for the parameter name, instead the input type was 'double'.

Error in findpeaks (line 71) [X,Ph,Pd,Th,Np,Str,infIdx] = parse_inputs(Xin,varargin{:});

Error in Example (line 2) [pks,locs]=findpeaks(T,x,'MinPeakDistance',3);

Sadly, I'm not seeing the redline. Would you know where I messed up?

[Mohammad Abouali]

Which version of MATLAB do you have?

When I run above code I get the red line that you have in your rough sketch. I am out of the limit to upload any figures, I can just upload 10 figures a day.

[Mohammad Abouali]

When I run the above code I get the following image:

If you have older matlab try this:

load Example
[pks,locs]=findpeaks(T,'MinPeakDistance',1500);
plot(x,T);
hold on
plot(x(locs),pks,'r','LineWidth',3)

[dj]

Wow, typing x in front of (locs) makes THIS much difference? This is so weird. Yes, I do have R2013a version. Thank you, everyone. Sorry about the late feedback.

[Mohammad Abouali]

I am guessing the x was not supported in the former version of MATLAB. Not sure but I think even R2014a didn't support it.