Fix the trace in the plot

Is there a way somehow to get rid off the cross-line in this traces? For some reason,I am getting this cross-line that I do not want to! Any suggestions? Thanks

[Stephen23]

We need to see your data. Please upload it: click the paperclip button, then both the Choose file and Attach file buttons.

Answer 1

[Star Strider]

Without your data, it’s difficult to say. One way would be to delete the last element of each of your x and y vectors:

x = [1:10 1];
y = randi(9, 1, 10);
y = [y y(1)];

figure(1)
subplot(2,1,1)
plot(x, y)                                  % Original Data
subplot(2,1,2)
plot(x(1:end-1), y(1:end-1))                % Delete Wrap-Around

Run this little code snippet to see the cause and effect of the change.

[sally_wu]

And I do not understand your suggestion...

[Star Strider]

As I mentioned as an example in my Answer, do this:

plot(a(1:end-1), b(1:end-1)) 
grid on

in both figures.

[sally_wu]

ref=81;
slice=500;
A1 = loaddata('a2.txt');
d =size(A1);
j=0;
for i=1:d(1,1);
if(A1(i,1)==slice);
   j=j+1;
  a(j,1)=A1(i,2);  
  b(j,1)=A1(i,4)-ref;
end
plot(a(1:end-1), b(1:end-1))
grid on
end

My apologies, but it did not work out...I am still getting that annoying cross-line, which I do not want to..

[Star Strider]

Please upload your data, preferably as a .mat file. Without having it to work with, I can only guess as to what the problem is (and thus far, that doesn’t seem to be productive for either of us).

Use the ‘paperclip’ icon to upload it, and then complete both the ‘Choose file’ and ‘Attach file’ steps.

Answer 2

[Azzi Abdelmalek]

Get ride of the last point in your plot

Answer 3

[Geoff Hayes]

sally - I suspect that if you are plotting something similar to

 plot(x,y)

then some of your x values are out of order (i.e. 5000,5001,6799,6800,5002,5003,etc). For example, if I want to plot the curve

 y = x^2;

where x is defined as

 x = linspace(-25,25,1000);

which I then re-arrange (or sort out of order) the x values as

 x = [x(251:end) x(1:250)];

I will observe the following upon plotting

 y = x.^2;
 plot(x,y)

I get the same "cross-line" as you! To correct, you can try to sort the x and y values as

 data = sortrows([x' y']); % sort on first column
 x = data(:,1);
 y = data(:,2);
 plot(x,y);

which should plot as expected without the undesirable line.