how to make different points movable in MATLAB

I wanted help in making different point moving with constant velocity. All points should be moving at constant speed.

Answer 1

[Walter Roberson]

Use scatter and record the handle . Loop updating the XData and YData properties of the handle and drawnow()

[passioncoding]

h=msgbox('Select Obstacles using the Left Mouse button,to select the last obstacle use the Right button');
  xlabel('Select Obstacles using the Left Mouse button,to select the last obstacle use the Right button','Color','blue');
uiwait(h,10);
if ishandle(h) == 1
    delete(h);
end
while but == 1
[xval,yval,but] = ginput(1);
xval=floor(xval);
yval=floor(yval);
plot(xval+0.5+yval+0.5,'ro');
end

I have used this code for creating random points( red circles) Now I want them to be moving with consatnt velocity ,like creating them random particles.

[Walter Roberson]

h=msgbox('Select Obstacles using the Left Mouse button,to select the last obstacle use the Right button');
  xlabel('Select Obstacles using the Left Mouse button,to select the last obstacle use the Right button','Color','blue');
uiwait(h,10);
if ishandle(h) == 1
    delete(h);
end

count = 0;
xvals = []; yvals = [];

while true
  [xval,yval,but] = ginput(1);
  if isempty(xval); break; end
  count = count + 1;
  xvals(count) = floor(xval);
  yvals(count) = floor(yval);
end

dx = randn(1, count);   %potentially a different velocity for each particle
dy = randn(1, count);

pointsize = 10;
h = scatter(xvals, yvals, pointsize, 'r');
for step = 1 : 100
    xvals = xvals + dx;
    yvals = yvals + dy;
    set(h, 'XData', xvals, 'YData', yvals);
    drawnow();
end

[passioncoding]

Thank you so much Walter.

How can I make these points move with specific velocity and direction with this equation

Xobs_new= Xobs+ Vobs* cos(theta)

Ynew_obs= Yobs+Vobs*sin(theta)

[Walter Roberson]

Vobs and theta are undefined. Is theta intended to be atan2(y, x) ?

[passioncoding]

Since I want to make the points moving with constant velocity, Vobs can be fixed number. Secondly yes its a theta, direction for particels/point to move forward.

[Walter Roberson]

%need _some_ Vobs and theta
theta = rand() * 2 * pi;
Vobs = rand() * 10;

h=msgbox('Select Obstacles using the Left Mouse button,to select the last obstacle use the Right button');
  xlabel('Select Obstacles using the Left Mouse button,to select the last obstacle use the Right button','Color','blue');
uiwait(h,10);
if ishandle(h) == 1
    delete(h);
end
count = 0;
xvals = []; yvals = [];
while true
  [xval,yval,but] = ginput(1);
  if isempty(xval); break; end
  count = count + 1;
  xvals(count) = floor(xval);
  yvals(count) = floor(yval);
end
dx = Vobs * cos(theta);
dy = Vobs * sin(theta);
pointsize = 10;
h = scatter(xvals, yvals, pointsize, 'r');
for step = 1 : 100
    xvals = xvals + dx;
    yvals = yvals + dy;
    set(h, 'XData', xvals, 'YData', yvals);
    drawnow();
end