I need to plot a Dynamic scattered plot. I have vector x and y, and those are coordinates. I need to plot coordinate 1, and then coordinate 2 but coordinate 1 must need to still there.

Hi everyone, i need to do a dynamic plot.I have 2 vectors, x & y. So i have a coordinate (x,y). For example, i have (0,0) , (1,1), (3,3) , (4,4) and so on, and first i need a point or a dot at (0,0) and then (1,1). then (2,2) but (0,0) and (1,1) must still there in the plot. So the plot will be like a lot of points but ploted dynamically. This is my code:

clear all

clc

close all

table = readtable('laser_data.csv');
array = table2array(table); 
for i = 1:length(array)
  %LEFT
  hold on
  for k = 2:2:30
    x = -0.018+array(i,k);
    y = 0.0899+array(i,k+1);
    xlabel('Distancia en el eje X')
    ylabel('Distancia en el eje Y')
    title('Obstáculos')
    h = scatter(x, y, 10, 'r');
    drawnow limitrate
    %pause(0.00001)
  end
  drawnow
  %FRONT
  for k = 32:2:60
    x = 0.05620-array(i,k+1);
    y = array(i,k);
    xlabel('Distancia en el eje X')
    ylabel('Distancia en el eje Y')
    title('Obstáculos')
    h = scatter(x, y, 10, 'r');
    drawnow limitrate
   %pause(0.00001)
 end
 drawnow
 %RIGHT
 for k = 62:2:90
    x = 0.018-array(i,k);
    y = -0.0899-array(i,k+1);
    xlabel('Distancia en el eje X')
    ylabel('Distancia en el eje Y')
    title('Obstáculos')
    h = scatter(x, y, 10, 'r');
    drawnow limitrate
   % pause(0.00001)
end
drawnow

end

But it takes like 30 minutes to plot, and using this one: just takes 30 secs but i dont want lines, i want points.

table = readtable('laser_data.csv');
array = table2array(table); 
h = animatedline('Marker','none');
for i = 1:length(array)
    
    %LEFT
for k = 2:2:30
    x = -0.018+array(i,k);
    y = 0.0899+array(i,k+1);
    xlabel('Distancia en el eje X')
    ylabel('Distancia en el eje Y')
    title('Obstáculos')
    addpoints(h,x,y)
    drawnow limitrate
    %pause(0.00001)
end
    %FRONT
for k = 32:2:60
    x = 0.05620-array(i,k+1);
    y = array(i,k);
    xlabel('Distancia en el eje X')
    ylabel('Distancia en el eje Y')
    title('Obstáculos')
    addpoints(h,x,y)
    drawnow limitrate
   %pause(0.00001)
end
    %RIGHT
for k = 62:2:90
    x = 0.018-array(i,k);
    y = -0.0899-array(i,k+1);
    xlabel('Distancia en el eje X')
    ylabel('Distancia en el eje Y')
    title('Obstáculos')
    addpoints(h,x,y)
    drawnow limitrate
   % pause(0.00001)
end

end

Answer 1

[dpb]

h = animatedline('Marker','none');

There's your problem...

array=readmatrix('laser_data.csv');             % no point in a table to just convert to array...
hAL=animatedline('Marker','.','MarkerSize',3,'LineStyle','none');  % set a point marker, no line...
xlabel('Distancia en el eje X')                 % don't update static info every pass through loop
ylabel('Distancia en el eje Y')
title('Obstáculos')
for i=1:size(array,1)                           % length() is risky
  %LEFT
  for k = 2:2:30
    x = -0.018+array(i,k);
    y = 0.0899+array(i,k+1);
    addpoints(hAL,x,y)
    drawnow limitrate
    %pause(0.00001)
  end
  ...

Make same changes in rest. It would be better to factor code so don't have repeated identical loops with just constants changing between, but that's another exercise...

[Santiago Villamil]

Thanks, but i need to do the for loop in that way, because of the data, ill try and tell you, thanks

[dpb]

You can turn the loops into a function to which just pass constants, then call the function with the appropriate set in a single loop; avoiding write the identical loop code multiple times

But, as noted, that's really simpy code factoring and cleanup and not related to the root problem/symptom, simply suggestions for future coding patterns.

Did not the above (presuming you did follow through with the example as shown for the first loop witht he others) fix your problem?

[Santiago Villamil]

Well, it works faster. But the plot shows lines between the points, i need just the points. Thanks! I hope you can help me there.

[Santiago Villamil]

This work really fast, but i just need the end points ploting dynamically but not the lines. Thanks!

[Steven Lord]

% Sample data
x = 0:360;
y = sind(x);

% Set up the animatedline and the axes
h = animatedline('Marker', 's', 'LineStyle', 'none');
axis([0 360 -1 1]);

% Add points to the animatedline
for whichpoint = 1:numel(x)
  addpoints(h, x(whichpoint), y(whichpoint))
  drawnow expose
end

[Santiago Villamil]

Thank you very much! It helps a lot!!!

[dpb]

Huh. I don't know how I missed the 'LineStyle','none' parameter...what happens when just retype instead of cut 'n paste. Sorry about that...

[Santiago Villamil]

Thanks man, No problem!, it helps a lot also!!