Does anybody know how should I use animatedline in order to draw me an orbit immediately? (I have used drawnow and it doesn t work)

     %%%%%%%%%%%%Valori pentru Rcsc

%%%%Pozitiile si vitezele pe cele 3 axe

y0(1,1)=   743322.3616  ;                                     
y0(2,1)=   -6346021.219 ;                               
y0(3,1)=     -3394131.349 ;                                   
y0(4,1)=     5142.38067;        
y0(5,1)=   4487.44895   ;                    
y0(6,1)=     -7264.00872;                     
%%%%Timpul

tspan=[0 :8640];  

%%%%Masa(kg) si aria suprafetei satelitului (m^2)

m =    217 ;         %320;
A =   1.2;             %8;

%%%%Metoda Runge-Kutta de ordin 4

h=1;                                                                             
y = zeros(6, tspan(end)/h); 
y(:,1) = y0;

for i=1:(tspan(end)/h)    
    H=sqrt(y(1,i)^2+y(2,i)^2+y(3,i)^2);
    k_1 = proiectia(tspan(i), y(:,i), H, m, A, y(4:6, i));
    k1=double(k_1);
    k_2 = proiectia(tspan(i)+0.5*h, y(:,i)+0.5*h*k_1, H, m, A, y(4:6, i));
    k2=double(k_2);
    k_3 = proiectia((tspan(i)+0.5*h), (y(:,i)+0.5*h*k_2), H, m, A, y(4:6, i));
    k3=double(k_3);
    k_4 = proiectia((tspan(i)+h),(y(:,i)+k_3*h), H, m, A, y(4:6, i));
    k4=double(k_4);

      y(:,i+1) = double(y(:,i) + (1/6)*(k1+2*k2+2*k3+k4)*h);  
  end

%%%Distanta satelitului
Rcsc = ((y(1,:).^2 + y(2,:).^2 + y(3,:).^2).^0.5);
n=50;
%plot(tspan,Rcsc)
 %%Textured 3D Earth example
%
% Ryan Gray
% 8 Sep 2004
% Revised 9 March 2006, 31 Jan 2006, 16 Oct 2013

%%Options

space_color = 'k';
npanels = 180;   % Number of globe panels around the equator deg/panel = 360/npanels
alpha   = 1; % globe transparency level, 1 = opaque, through 0 = invisible
GMST0 = []; % Don't set up rotatable globe (ECEF)
%GMST0 = 4.89496121282306; % Set up a rotatable globe at J2000.0

% Earth texture image
% Anything imread() will handle, but needs to be a 2:1 unprojected globe
% image.

image_file = 'https://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Land_ocean_ice_2048.jpg/1024px-Land_ocean_ice_2048.jpg';

% Mean spherical earth

erad    = 6371008.7714; % equatorial radius (meters)
prad    = 6371008.7714; % polar radius (meters)
erot    = 7.2921158553e-5; % earth rotation rate (radians/sec)

%%Create figure

figure('Color', space_color);
orbit=animatedline(y(1,:),y(2,:),y(3,:),'Color','y');

hold on;

% Turn off the normal axes

set(gca, 'NextPlot','add', 'Visible','off');

axis equal;
axis auto;

% Set initial view

view(0,30);

axis vis3d;

%%Create wireframe globe

% Create a 3D meshgrid of the sphere points using the ellipsoid function

[x, y, z] = ellipsoid(0, 0, 0, erad, erad, prad, npanels);

globe = surf(x, y, -z, 'FaceColor', 'none', 'EdgeColor', 0.5*[1 1 1]);

%%Texturemap the globe

% Load Earth image for texture map

cdata = imread(image_file);

% Set image as color data (cdata) property, and set face color to indicate
% a texturemap, which Matlab expects to be in cdata. Turn off the mesh edges.

set(globe, 'FaceColor', 'texturemap', 'CData', cdata, 'FaceAlpha', alpha, 'EdgeColor', 'none');

I'm sorry for the appearance of the code!

Answer 1

[Meysam Mahooti]

You can use my different orbit propagators which all of them draw satellite's groundtrack after finishing propagation:

https://www.mathworks.com/matlabcentral/fileexchange/55167-high-precision-orbit-propagator

https://www.mathworks.com/matlabcentral/fileexchange/54877-satellite-orbit-modeling

https://www.mathworks.com/matlabcentral/fileexchange/66000-groundtrack

Answer 2

[Walter Roberson]

animatedLine() is for the case where you want to add new data points to an existing line, possibly with a "trail" of previous points behind it. It is not used to create a static set of points that are to be highlighted in sequence. If you want to establish the orbit once and have a point "travel around" it, use comet() instead.

[Alexandru Lapusneanu]

What I wanna do is that when I run the script a figure with the Earth should appear, and while the positions are being caluclated by the runge kutta algorithm it should upload the orbit in real time. But now the figure appears only after the Rk algorithm is being calculated till the end of tspan and the orbit from the figure is already uploaded without intermediate points. What should I do? I've seen on github that others use animatedline and drawnow.

[Walter Roberson]

At each time that you have an updated point, you should addpoints(orbit,x,y) it, and then call drawnow()

[Alexandru Lapusneanu]

I was thinking about

orbit=animatedline;
addpoints(orbit,y(1,:),y(2,:),y(3,:));
drawnow

But where should I put this line exactly? if I put it in the rk loop it doesn't work and if I put it

% Create figure
figure('Color', space_color);
orbit=animatedline;
addpoints(orbit,y(1,:),y(2,:),y(3,:));
drawnow

it first displays a figure with the orbit but not by intermediate points and then a different figure with the Earth ,while the orbit and the Earth should be in the same figure.

[Walter Roberson]

Only use animatedline once, and record the value like you did. Then lass orbit into the function where you calculate the new x and y positions. addpoints() as soon as you figure out the new coordinates.

[Alexandru Lapusneanu]

I've listened to your advice and put the addpoints in the loop and it describes the orbit correctly but the problem is that the line is being animated from 0 and it forms some sort of area.

[Walter Roberson]

Make sure you set the 'MaximumNumPoints' options when you create the animatedLine()

[Alexandru Lapusneanu]

I did this and the result is:

    figure;
    orbit=animatedline('MaximumNumPoints',length(tspan));

[Walter Roberson]

Please post your current code.

[Alexandru Lapusneanu]

%%%%%%%%%%%%Valori pentru Rcsc
tspan=[0 :86400];  
figure;
orbit=animatedline('MaximumNumPoints',length(tspan));

%%%%Pozitiile si vitezele pe cele 3 axe

y0(1,1)=   743322.3616  ;                                     
y0(2,1)=   -6346021.219 ;                               
y0(3,1)=     -3394131.349 ;                                   
y0(4,1)=     5142.38067;        
y0(5,1)=   4487.44895   ;                    
y0(6,1)=     -7264.00872;                     
%%%%Timpul

%%%%Masa(kg) si aria suprafetei satelitului (m^2)

m =    217 ;         %320;
A =   1.2;             %8;

%%%%Metoda Runge-Kutta de ordin 4

h=1;                                                                             
y = zeros(6, tspan(end)/h); 
y(:,1) = y0;

for i=1:(tspan(end)/h) 

      H=sqrt(y(1,i)^2+y(2,i)^2+y(3,i)^2);
      k_1 = proiectia(tspan(i), y(:,i), H, m, A, y(4:6, i));
      k1=double(k_1);
      k_2 = proiectia(tspan(i)+0.5*h, y(:,i)+0.5*h*k_1, H, m, A, y(4:6, i));
      k2=double(k_2);
      k_3 = proiectia((tspan(i)+0.5*h), (y(:,i)+0.5*h*k_2), H, m, A, y(4:6, i));
      k3=double(k_3);
      k_4 = proiectia((tspan(i)+h),(y(:,i)+k_3*h), H, m, A, y(4:6, i));
      k4=double(k_4);

      y(:,i+1) = double(y(:,i) + (1/6)*(k1+2*k2+2*k3+k4)*h);  

addpoints(orbit,y(1,:),y(2,:),y(3,:));
    drawnow
end

[Walter Roberson]

You had posted your proiectia function in https://www.mathworks.com/matlabcentral/answers/362671-how-can-i-succesfully-implement-an-adaptive-rk-method-without-getting-any-error-like-subscript-indi#answer_287161 but I had pointed out a number of bugs in that version, and I do not see that you have posted an updated version of it.

[Alexandru Lapusneanu]

There I was trying to implement an adaptive Rk and I succeded ,but the method is way too much time consuming and the results were almost the same as the simple RK. Indeed for that method I had to make some changes , but the simple method works very good in this format.