How to make a "moving" graph for a real time signal along the x-axis?

Hi All,

I have a piece of code that simulate the plotting of a signal in real time up to 1000 point.

% the data
     np=1000; 
% prepare the plot
     x=1:np;
     y=-inf*ones(size(x));
     lh=line(x,y);
     shg;
% Plot data live
for i=1:np
     ix=rem(i-1,np)+1;
     y(ix)=.10*fix(i/np)+rand; % <- new data
     set(lh,'ydata',y);
     pause(.0001); 
end

I would like to seek your help on how to make the data "move" along the x-axis. Foe example, after the graph plot from 0 to 50 point. The origin 0 change to start from 51 to 100. Then 100 change to 101. I would like the plot to "Scrolled" towards the left. The purpose of me implementing this function is because the data is getting "cramp up" for displaying all the data from 0 to 1000. I think my description is not very good. I had included a youtube link which is similar to what that I would like to achieve.

https://www.youtube.com/watch?v=d3B4akZiHgo Thank You!

[John BG]

you may consider axis shifting x1, dx y1 y2 constant

axis([x1 x1+dx y1 y2])

and apply drawnow after each plot so the graph is updated

John BG <mailto:[e-mail] [e-mail]>

Answer 1

[John BG]

Hi Jeff

this is John BG ( <mailto:[e-mail] [e-mail]> )

you may consider axis shifting x1, dx y1 y2 constant, with

    axis([x1 x1+dx y1 y2])

and apply drawnow

   for ..

    plot(..);drawnow 

    end

after each plot in the loop so the graph is updated accordingly.

A simple implementation is:

clear all;clc

x=[0:.01:16]
y=sin(3*x)

figure(1);hold all
Dx=50;y1=-1.2;y2=1.2;

for n=1:1:numel(x)

      plot(x,y);axis([x(n) x(n+Dx) y1 y2]);drawnow

end

The link supplied by Jan Simon is a search result in the MATLAB exchange, some of the results are static, there are sliders on plots, I understood that you want it shifting, like the YouTube example you mention in the question, correct?

If you find this answer useful would you please be so kind to mark my answer as Accepted Answer?

To any other reader, please if you find this answer

please click on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

[Jeff Bryan]

Thank You very much! It works

[Caleb Schear]

this works fine, is there any way to make the code halt when I click exit, it just keeps running until the X axis reaches 16

Answer 2

[Jan]

This is a common problem and as usual several people have posted solutions in the FileExchange:

https://www.mathworks.com/matlabcentral/fileexchange/?utf8=%E2%9C%93&term=scroll+plot

Answer 3

[Risith Ravisara]

hear is the code

    T = 500;
    passo = 1;
    t=1;
    x=0;

    while 1
        b=analogRead(a,0);
        x=[x,b];
        plot(x);
        %pay attention to this command %
        axis([T*fix(t/T),T+T*fix(t/T),0,1024]); 
        grid
        t=t+passo;
        drawnow;
    end

Answer 4

[Caleb Schear]

what I did was just put

xlim([(i-10) i])

after the pause function

it worked but if it moves too fast change the pause time or enlarge the i-n value (I used 10 it can be much larger)

[Bala Naga Jyothi V]

I am looking to track the realtime moving object to plot the history data.

But nothing is working either drawnow,etc..,

function setax(Position, srf_in)

figure(1)

hold off

srf_in = srf_in + repmat([Position(1) Position(2) Position(3)],[16 1])

h=plot3(srf_in(:,1),srf_in(:,2),srf_in(:,3),'b',"MarkerSize",10);

% h.Color = 'red';

hold on

ax = gca;

ax.FontSize = 12;

ax.TickDir = 'out';

ax.TickLength = [0.02 0.02];

ax.XLim = [-50 50];

ax.YLim = [-50 50];

ax.ZLim = [-50 50];

addpoints(h,Position(1), Position(2),Position(3));

drawnow

% ax.XLim = [-110 110];

% ax.YLim = [-110 110];

% ax.ZLim = [-110 110];

xlabel('X (m)');

ylabel('Y (m)');

zlabel('Z (m)');

grid on

% end

end