How to plot data point by point and erasing the last one?

Hello, I need to plot my data point by point, but I also need just one point on the plot (when new point arrived the one before to disappear). That is my code everything works good I just want to fix that:

y=[1,3,2,3,3];
n=numel(y)
figure 
xlim([0 2])
ylim([0 2])
grid on
hold on
for ii=1:n
    if y(ii)<1.1
    scatter(0.5,0.5),hold on
    pause(1)
    else if y(ii)<2.2
    scatter(1.5,1.5),hold on
        else
    scatter(0.5,1.5)
    pause(1)
        end
    end
end

Answer 1

[MHN]

I have done pretty much animated plot with Matlab, What you need is a little trick !!

y=[1,3,2,3,3];
n=numel(y)
figure 
xlim([0 2])
ylim([0 2])
grid on
hold on
for ii=1:n
    if y(ii)<1.1
    scatter(0.5,0.5)  ,hold on
    pause(1)
    scatter(0.5,0.5,'w')  ,hold on
    else if y(ii)<2.2
    scatter(1.5,1.5) ,hold on
    pause(1)
    scatter(1.5,1.5, 'w') ,hold on
        else
    scatter(0.5,1.5)
    pause(1)
    scatter(0.5,1.5,'w')
        end
    end
end

[Miroslav Mitev]

Thanks a lot MHN :)

[Deepika]

hello...I need to plot the moving point in such a way that when this moving point go to boundary of this simulation area then it will not reflect back but it will go outside the boundary and disappear and then at the same time from the opposite direction at same angle (at which the previous point was disappeared ) ,the new point will get appear.

Here is my code,It works good but still not got the desired output so please help me for getting the output as mentioned above.....

clear all;

clc;

% ................parameters........................

MAX_X= 100;

MAX_Y =100;

NODES = 50;

tim_sim=3;

alpha=0.99;

velocity =10;

direction =60;

mean_velocity=mean(randn(5),'all');

mean_direction=mean(randn(5),'all');

%....................scan all existing nodes..................

x_tmp1=[];

y_tmp1=[];

for nb=1:NODES

x= (0 + (MAX_X-0)*rand);

y= (0 + (MAX_Y-0)*rand);

%..............node position in every instant t...........

for t=1:tim_sim

%...calculate the new position by using the new_formula of Gauss-Markov...

x_tmp = x + velocity * cos(direction);

x_tmp1=[x_tmp1 x_tmp];

y_tmp = y + velocity * sin(direction);

y_tmp1=[y_tmp1 y_tmp];

normal_velocity=normrnd(0,1);

normal_direction=normrnd(0,1);

%..calculate the new velocity and new direction by using the newformula of

%Gauss-Markov..

velocity_tmp=(alpha*velocity+(1-alpha)*mean_velocity+sqrt(1-alpha*alpha)*normal_velocity);

direction_tmp=(alpha*direction+(1-alpha)*mean_direction+sqrt(1-alpha*alpha)*normal_direction);

% .....node bounces on the margins......

if (x_tmp1<0)

x_tmp1 = -1.*x_tmp1;

direction = pi-direction;

mean_direction = pi-mean_direction;

end

if (x_tmp1>MAX_X)

x_tmp1 = 2*MAX_X - x_tmp1;

direction = pi-direction;

mean_direction = pi-mean_direction;

end

if (y_tmp1<0)

y_tmp1 = -1.*y_tmp1;

direction = -direction;

mean_direction = -1*mean_direction;

end

if (y_tmp1>MAX_Y)

y_tmp1 = 2*MAX_Y - y_tmp1;

direction = -direction;

mean_direction = -1*mean_direction;

end

% plot(x_tmp1,y_tmp1,'color',[0.3 0.3 1])

end

%.......................Animation.......................

n=length(y_tmp1);

% plot(x_tmp1,y_tmp1,'*')

% axis([0 MAX_X 0 MAX_Y])

% pause(0.05)

for i=1:n

plot(x_tmp1(i),y_tmp1(i),'*')

axis([0 MAX_X 0 MAX_Y])

pause(0.05)

end

end

xlabel('X (meters)');

ylabel('Y (meters)');

Answer 2

[Steven Lord]

Instead of creating two new scatter plots each step (one to cover the previous point in white, the other to create the new point) just update the coordinates of the point.

x = 0:360;
y = sind(x);
h = plot(x(1), y(1), 'o');
axis([0 360 -1 1])
for k = 2:numel(x)
    drawnow expose
    h.XData = x(k);
    h.YData = y(k);
end