- using max and find, find the highest value (peak) and it's position (index)
- using simple logic, find which maximum is "further" (which index is higher). then, find the difference between the distances of peak (difference in index numbers)
- using NaN, create vector full of NaNs, the length will be length of the original data + difference of the maximum indexes
- using indexing and knowledge about position of the peaks, insert your data into your NaN vector.
How to shift data sets automatically
15 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Damaris Litton
am 23 Mär. 2023
Beantwortet: Mathieu NOE
am 27 Mär. 2023
I have two sets of data that produce curves (see attached), and I want to analsye them both so need the data points to line up. Is there a code I can use to get Matlab to line up the data points for me? i.e the peak point for U should be the same data point as the one for D. The matrices are the same size but can be shortened if necessary to do this.
3 Kommentare
Vilém Frynta
am 23 Mär. 2023
hello,
yes.
% load data
load U.mat
load D.mat
% make vectors from your data (previously columns)
U = U'
D = D'
% find maxs (peaks)
idx.U = find(U == max(U));
idx.D = find(D == max(D));
% difference between the peaks
idx.diff = idx.U - idx.D
% let's assume U is further
is_U_further = 1;
% find if D is further (if idx.diff is negative)
if idx.diff < 0
is_U_further = 0;
idx.diff = idx.D - idx.U % switch the difference in that case
end
% create NaN vector and new variables
L = length(U);
new.U = NaN([1 L+idx.diff]);
new.D = NaN([1 L+idx.diff]);
% fit the values so the peaks are at the same index
if is_U_further == 1; % if U is further... do this:
new.U(1:L) = U;
new.D(idx.diff:idx.diff+L-1) = D; % move D further, so it matches
end
if is_U_further == 0;% if D is further...
new.D(1:L) = D;
new.U(idx.diff:idx.diff+L-1) = U;
end
plot(new.U)
hold on
plot(new.D)
thought i did it wrong but it looks like "D" is just too small (no pun intended). you can try to strech that or make new, relative Y axis for it.
Akzeptierte Antwort
Mathieu NOE
am 27 Mär. 2023
hello
myabe this ?
I took the options to have both peaks overlaid and also the two curves have same initial y value
This is the result
of course you can change the code if your prefer to have same y final value but I doubt you can have start, end and peaks points all 3 overlaid
% load data
load U.mat
load D.mat
% find maxs (peaks)
[umax,iumax] = max(U);
[umin,iumin] = min(U);
% dU = umax- umin;
dU = umax- U(1);
[dmax,idmax] = max(D);
[dmin,idmin] = min(D);
% dD = dmax- dmin;
dD = dmax- D(1);
% D y dir stretch factor
D_ySt = dU/dD;
D = D*D_ySt;
% apply y shift to have both curves start at same value U(1)
yshift = D(1) - U(1);
D = D - yshift;
% x axis shift to align both peaks (delay D vs U)
xshift = iumax - idmax;
% define x axis vectors
xu = 1:numel(U)
xd = xu + xshift;
plot(xu,U,xd,D)
0 Kommentare
Weitere Antworten (0)
Siehe auch
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!