How to clear all fitting settings?

I'm plotting some data from a 2068 by 5 matrix (spectra.m) using this code:

load 'spectra.mat'
hold on
for i = 2:5
plot(spectra(:,1), spectra(:,i), 'LineWidth', 7)
end

Every time I run the script, it comes up with a plot of the data as expected but each line has linear fit to it (see picture). Though I'm not sure if it's a fit or some other effect...

I've already tried clearing the work-space and restarted Matlab, in case I've inadvertently changed some settings. However, this didn't make any difference...In fact, if I plot some data from other projects, everything works fine so there must be a problem with the way I'm plotting the matrix!

Any help would be very much appreciated :)

[Azzi Abdelmalek]

The provided code does not give enough details about your problem

[odo22]

This is literally the only piece of code I'm using...I have a second part which I omitted for clarity but I don't think it's the source of my problem:

xlim([450, 800]);
ylim([0.0,0.35]);
set(gca,'FontSize',15)
set(findall(gcf,'type','text'),'FontSize',50)
ax = gca;
set(gca,'XMinorTick','on','YMinorTick','off')
ax.FontSize = 50;
ax.YTick = [0.1 0.2 0.3 ];
ax.XTick = [ 500 600 700 800];
ax.Box = 'on';
ax.LineWidth = 7;
hold off

Even if I delete this second part from my script, it still plot the straight lines alongside my data :(

Answer 1

[Stephen23]

It is your data. They are not in sequence along the X axis, and so this is how the Y values are plotted.

Something like this:

>> X = [0:0.01:3*pi/2,0]; % the RHS zero is out of sequence!
>> Y = sin(X);
>> plot(X,Y)

[odo22]

Thank you so much!

My data was in the correct order but for some reason the matrix was filled with zeros at the bottom (i.e. the bottom rows)...

I got rid of them and now it works!

Thanks once more!