A moving point plot in MATLAB figure with animation between 2 point

Hi everybody; i want to make a moving point animation between a = [41.50,-70.95] b = [ 41.80 , -70.5].How can i do this?

Answer 1

[Geoff Hayes]

Farhad - what kind of animation do you want? Should the point follow a straight line, or do something else? If the former, then try the following

 a = [41.50,   -70.95];
 b = [ 41.80 , -70.50];

 % straight line function from a to b
 func = @(x)a(2) + (a(2)-b(2))/(a(1)-b(1))*(x-a(1));

 % determine the x values
 x = linspace(a(1),b(1),50);

 % determine the y values
 y = func(x);

 % create the figure
 figure;

 % get a handle to a plot graphics object
 hPlot = plot(NaN,NaN,'ro');

 % set the axes limits
 xlim([min(a(1),b(1)) max(a(1),b(1))]);
 ylim([min(a(2),b(2)) max(a(2),b(2))]);

 % iterate through each point on line
 for k=1:length(x)
     % update the plot graphics object with the next position
     set(hPlot,'XData',x(k),'YData',y(k));

     % pause for 0.5 seconds
     pause(0.5);
 end

So on each iteration of the for loop, we just replace the (x,y) coordinate of the last drawn point with the new one and then wait for half a second before drawing the next point, which creates a kind of animation.

[Farhad]

First of all thanks for your code,it is exactly what i want,but i must show location data in another window(think i must use sprintf),and this location must be deponds in time,have you any idea about this?

[Geoff Hayes]

By another window, do you mean a static text box? Do you want to design a GUI with an axes object and a text control? if so, start with creating the GUI using GUIDE...

[Farhad]

ok thanks :)

[Farhad]

soryy Geoff Hayes,if i want show the point coordinats near the red point,what should i do?

hTxtcoords= text(y(1,1), y(1,2), sprintf('(%.2f,%.2f)',y(1,:)),'Color',[0.2 0.2 0.2], 'FontSize',8,'HorizontalAlignment','left', 'VerticalAlignment','top');
set(hTxtcoords, 'Position',x(k,:), 'String',sprintf('(%.3f,%.3f)',y(k,:)))

i use those code but,cant work. have you any idea?

[Geoff Hayes]

Farhad - i suspect that the problem that you are having is in the use of the x and y coordinates. At each iteration of the for loop, you will want to place the text box at the position x(k),y(k) and use that same position in the sprintf. Like with the plot, create (outside of the for loop) the handle to the text object as

 hTxtcoords = text(NaN,NaN,'','FontSize',8,'HorizontalAlignment','left', 'VerticalAlignment','top');

and then within the for loop, add the following line after the plot "update" and before the pause

 set(hTxtcoords, 'Position',[x(k) y(k)], 'String', ...
     sprintf('(%.3f,%.3f)',x(k),y(k)));

Try the above and see what happens!

[Farhad]

Thank you Geof,i will say my regards to you in presentation.

[passioncoding]

Can I ask same question related to this kind a animation? plz help me