Plotting datapoints with their time distance on x-axis

Hello everyone!

I want to ask something but i'm not sure if iteven possible to do that. I have data that looks like this (only a small part of it):

What my code does is getting the timedifference of each pair (sometimes there are 3 points, sometimes 4, but i'm only interested in the first and last one) and calculates the travelled distance between those points. The result looks like this (the red line is not of interest):

What i'm supposed to do is match the travelled distance to the timepoints above. If I have to describe the expected result, i would say the following: the travelled distance between aprox. 100.5s and 102s is 12cm, after that it is 16cm from 102s till 105s and so on.. I hope you get what I mean.

I attached the needed data in question.mat. To get the plots above i did the following:

load question.mat

r_Trommel = 1;
r_0=0.319;
kmh=15;

figure(1)
plot(t(index_1:index_2-1),Betrag_Ableitung);
hold on
plot(max_XWerte,max_YWerte,'mo');
hold off

k=1;
while (k>=1) && (k<=length(max_XWerte)-3)
    if (abs(max_XWerte(k+3)-max_XWerte(k))> 0.05) && (abs(max_XWerte(k+3)-max_XWerte(k))< 0.08)
        laenge(k) = abs(max_XWerte(k+3)-max_XWerte(k))*(kmh/3.6);
        k = k+4;
    elseif (abs(max_XWerte(k+2)-max_XWerte(k))>= 0.03) && (abs(max_XWerte(k+2)-max_XWerte(k))< 0.09)
        laenge(k) = abs(max_XWerte(k+2)-max_XWerte(k))*(kmh/3.6);
        k=k+3;
    else
        laenge(k) = abs(max_XWerte(k+1)-max_XWerte(k))*(kmh/3.6);
        k=k+2;
    end
end
for m=1:length(laenge)
    if laenge(m) == 0
        laenge(m) = laenge(m-1);
    end
end
for f=1:length(laenge)
        l_test(f)=100*(2*r_Trommel*asin(laenge(f)/(2*r_Trommel)));
end
x=0:1:length(l_test)-1;
figure(2)
plot(x,l_test)

Thank you in advance!!

Answer 1

[Cris LaPierre]

It's hard to say for certain, since you have not shown how the times correspond to your step plot, but here's some simple code that may get you close. It is wrong because max_XWerte has more elements than l_test, so the last few times in max_XWerte are not used.

load KPvars.mat % variables created by your code

% Find the index of each step change
step = [1 find(abs(diff(l_test))>0.0001)+1];

% use indeces to find the start and stop time of each step
start = max_XWerte(step(1:end-1));
stop = max_XWerte(step(2:end));

% use indices to find the corresponding distance traveled
dist = l_test(step(1:end-1))';

% Combine into a table
T = table(start,stop,dist)

T = 44×3 table
    start      stop      dist 
    ______    ______    ______

    100.54    102.69    12.508
    102.69    107.72    16.686
    107.72     110.6    12.508
     110.6    112.77    20.871
    112.77    113.49    12.508
    113.49    117.07    8.3357
    117.07    120.69    12.508
    120.69    121.43    8.3357
    121.43    125.02    12.508
    125.02    126.41    8.3357
    126.41    127.18     33.49
    127.18    132.21    12.508
    132.21    135.82    20.871
    135.82    136.54    12.508
    136.54    137.25    8.3357
    137.25    140.11    12.508

[Kevin Pollmer]

Thank you for the answer!

This might also solve the problem. The supervisor of my student research paper wanted to have a clear output of the time intervall and the calculated distance travelled . He mentioned a plot, but a table should be sufficient enough :D