Smoothing plots in MATLAB

Hello. I am trying to smooth my graph by applying the moving average filter. I have searched and discovered that there exists a function smooth(), which can easily make your curve smoother. Since I don't have this function, I have been trying to either code my own smoothing function, or download already written functions. However, none of them worked so far. Could anyone give me some advice on this? Thanks. My graph is the one given in the figure. (46 indexes, each index plotted with different colour.)

My code is as follows.

   maxind = 46;
 colortab = jet(maxind);  %distinct colors
 figure
 hold on 
 for ind=1 : maxind,
   plot(plane_des2(ind).Altitude, plane_des2(ind).IAS,'-', 'Color', colortab(ind,:));
   if ind == 1  %save time on the rest
     xlabel('Horizontal Displacement');
     ylabel('Unfiltered Airpseed');      
     title('Airpseed vs Displacement');
   end
 end
 hold off

Thanks.

Answer 1

[Thorsten]

To generate a smoothed version xs of x, you can average over n elements, i.e., n = 3, with the following one-liner:

n = 3; xs = conv(x, 1/n*ones(1,n), 'same')

[bio lim]

Could you help me by implementing it into my code? I am a complete beginner, sorry. Thanks!

[Thorsten]

n = 3; % or a 5 or 7 etc if you want higher smoothing
for ind =1:maxind
  y = plane_des2(ind).IAS;
  ys = conv(ys, 1/n*ones(1,n), 'same');
  plot(plane_des2(ind).Altitude, ys, '-', 'Color', colortab(ind,:));
end

% outside the for loop
hold off

xlabel('Horizontal Displacement');
ylabel('Unfiltered Airpseed');      
title('Airpseed vs Displacement');