Find all intercepts for all parameter values

Hi,

In the attached the fig. I have different intercept for different values of xi. I plotted the figure from COMSOL. Please how can I find all the intercepts in matlab and plot them against xi ?

[Walter Roberson]

Can you get access to the data, or are you limited to getting an image of the plot (like this png file) ?

[University]

At moment I can't get access to the data because I have uninstall my COMSOL to install a new one that can work with MATLAB.

[Walter Roberson]

I suggest you look at https://www.mathworks.com/matlabcentral/fileexchange?q=tag%3Adigitize

[Torsten]

And what intercepts are you talking about ? Intercepts with the axis "velocity = 0" ? Intercepts of the curves themselves ?

[University]

While, at the monent this is velocity component in the y-direction verse the xi plot. I actually want to plot the y_intercept (which is the position) verse the xi. In which case, i need to compute y_intercept.

Answer 1

[Matt J]

As an example,

y=linspace(-1,1,1000);
V=sin(pi*y-0.4); %fake input data

loc=diff(sign(V)) & abs(y(1:end-1))<0.5;

yintercept=y(loc),

yintercept = 0.1271

plot(y,V,yintercept,0,'rx'); yline(0);
xlabel y-coordinate; ylabel Velocity

[University]

Hi Matt,

Thank you for your assistant. I will try this

[Matt J]

You're welcome, but if it works please Accept-click the answer.