My goal output is to have four plots displaying (time, dist_a), (time, speed_a), (time, dist_b), and (time, speed_b) when looping through a multidimensional array. However, I am displaying only 2 blanked plots.
Here is my code:
time = rand(10, 1)
dist_a = rand(10,1)
dist_b = rand(10,1)
speed_a = rand(10,1)
speed_b = rand(10,1)
dist = cat(2, dist_a, dist_b);
speed = cat(2, speed_a, speed_b);
for k = 1:2
figure;
plot(time, dist(k));
plot(time, speed(k));
end
Your problems were two-fold. Firstly, you were only plotting a single point as opposed to a vector, changing dist(k) to dist(:,k) for example fixes this. Secondly, if you want four figures with a loop that executes twice, you need to include another figure command before the second plot. The following should do what you asked for, I also added in some formatting to make the plots looks nicer
for k = 1:2
figure
plot(time, dist(:,k),'o','LineWidth',2);
xlabel('time')
ylabel('distance')
box on
grid on
figure
plot(time, speed(:,k),'o','LineWidth',2);
xlabel('time')
ylabel('speed')
box on
grid on
end
which gives:
Related
I currently want to have the legend of graph, however i'm plotting several lines that should be group in only 3 types.
My currently option is to use a dummy plot out of the boundaries, plotting the relevant data and calling the legend just at the end. It works but it is prone to errors. I wanted to update the legend and select just a few of the plots.
I tried to use the leg_handle.String, but then it comes two problems:
It still plot 5 handles instead of 3.
It does not have the proper line style & color.
Any ideas?
Bellow follow the code (with dummy plot commented) and the pictures of the current version giving the error and what i want to look.
clear
figure()
hold on
%using
%dummy plot
% leg_text={'a','b','c'};
% plot(100,100,'-r')
% plot(100,100,'-b')
% plot(100,100,'-k')
for ii=1:20,
plot(1:11,linspace(0,ii,11),'-r')
end
for ii=30:50,
plot(1:11,linspace(0,ii,11),'-b')
end
for ii=70:80,
plot(1:11,linspace(ii,25,11),'-k')
end
Yaxl=[-1 80];
Xaxl=[1 11];
set(gca, 'Visible','on', ...
'Box','on', ...
'Layer','top',...
'Xlim',Xaxl, ...
'Ylim',Yaxl);
%using
% legend(leg_text)
%want to use
leg_hand=legend(gca,'show');
leg_hand.String=leg_hand.String([1 21 42]);
%extra comand will give the things that i wanted above
% leg_hand.String=leg_hand.String([1 2 3]);
What it gives:
What I expect to have:
I have tried this method using [a,b,c,d]=legend, but this give only the a handle that i already using.
This little workaround should do the job:
clear();
figure();
hold on;
h = gobjects(3,1);
for ii = 1:20
h(1) = plot(1:11,linspace(0,ii,11),'-r');
end
for ii = 30:50
h(2) = plot(1:11,linspace(0,ii,11),'-b');
end
for ii = 70:80
h(3) = plot(1:11,linspace(ii,25,11),'-k');
end
set(gca,'Box','on','Layer','top','Visible','on','Xlim',[1 11],'Ylim',[-1 80]);
legend(h,'A','B','C');
hold off;
Actually, what I did is very simple. I created an array of graphical objects of size 3 (one for each iteration) using the gobjects function. Then, inside each iteration, I assigned the last plotted line to its respective array placeholder. Finally, I created the legend using the three graphical objects I previously stored.
Alternatively:
clear();
figure();
hold on;
h1 = gobjects(20,1);
for ii = 1:20
h1(ii) = plot(1:11,linspace(0,ii,11),'-r');
end
h2 = gobjects(21,1);
for ii = 30:50
h2(ii-29) = plot(1:11,linspace(0,ii,11),'-b');
end
h3 = gobjects(11,1);
for ii = 70:80
h3(ii-69) = plot(1:11,linspace(ii,25,11),'-k');
end
set(gca,'Box','on','Layer','top','Visible','on','Xlim',[1 11],'Ylim',[-1 80]);
legend([h1(1) h2(1) h3(1)],'A','B','C');
hold off;
You create an array of graphical objects for storing the plot handlers produced by every iteration. Then you create the legend using the first (basically, any) item of each array of graphical objects.
I am trying to plot variables dynamically in MATLAB. I have an array (set of states) that needs to be plotted with time. I tried plot(time,theta), where theta is a 1*5 array. With this command, I get an error saying that theta should be a scalar because time is a scalar. I then tried using for-loop to plot(time,theta(i)). The problem with this is that I get data points at discrete time intervals on my plot. However I need a continuous plot. I wonder how this can be done.
You need to use hold on when plotting.
For example:
time = 1;
theta = [1:100];
figure
for i=1:100
plot(time, theta(i),'r.')
hold on %--> Keeps the previous data in your plot
time = time + 1;
end
Let's see if I get this straight. Time is updated at every step, and theta are five different variables that also get updated. This should work for you:
% Use your own time variable
time = 1:100;
figure; hold on;
h = cell(5,1); % Handles of animated lines
colors = 'rgbkm'; % Colors of lines
for t = time
theta = randn(5,1);
if isempty(h{1})
% Initialize plot
for k = 1 : 5
h{k} = animatedline(t , theta(k) , 'LineStyle' , '-' , 'Color' , colors(k));
end
else
% Update plot with new data
for k = 1 : 5
addpoints(h{k}, t , theta(k));
end
end
% Update plot
drawnow
end
The object animatedline was introduced in R2014b. You can still do something similar with a conventional plot and updating the XData and YData properties of the lines at each loop.
I need to prevent a specific plot entry from being displayed on a Matlab plot legend.
Sample:
% x and y are any plot data
for i=1:5
plot(x,y);
plot(x2,y2,'PleaseNoLegend!'); % I need to hide this from legend
end
legend('show');
Is there any flag I can set inside the plot command so this specific entry doesn't show up in legend?
You can achieve that by setting the 'HandleVisibility' property to 'off'. Note that this hides the handles of those plots to all functions, not just to legend.
For example,
hold on
for k = 1:3
x = 1:10;
y = rand(1,10);
x2 = x;
y2 = y + 2;
plot(x,y);
plot(x2,y2,'--','HandleVisibility','off'); % Hide from legend
end
legend('show')
produces the graph
You can use the semi-documented function called hasbehavior, that allows you to ignore individual plots in a legend after you issued the plot command.
figure;
hold on;
for i=1:5
plot(x,y);
h = plot(x2,y2);
hasbehavior(h,'legend',false);
end
legend('show');
The fact that it's semi-documented suggests that it could break sooner or later in a newer MATLAB version, so use with care. It might still be a convenient choice for certain applications.
As #stephematician noted, this MATLAB built-in is also unavailable in Octave, which might be another reason why the other answers are preferable.
As Luis Mendo mentions (and I somehow missed this) the handle is hidden to all other functions in his answer, which will be ok in most situations, but an alternative solution which looks identical to the above and doesn't have this effect is:
k_values = 1:3;
h = nan(size(k_values));
x = 1:10;
hold on
for k = k_values
y = rand(size(x));
y2 = y + 2;
h(k) = plot(x,y);
plot(x,y2,'--');
end
hold off
legend(h, strcat('data', num2str(k_values')))
The final command sets the legend entry for each handle returned by the plot(x,y) command. The first argument is a 1x3 array of line handles which will appear in the legend, and the second argument is a 3x5 char matrix where each row is a label.
I want to update a plot with multiple data lines/curves as fast as possible. I have seen some method for updating the plot like using:
h = plot(x,y);
set(h,'YDataSource','y')
set(h,'XDataSource','x')
refreshdata(h,'caller');
or
set(h,'XData',x,'YData',y);
For a single curve it works great, however I want to update not only one but multiple data curves. How can I do this?
If you create multiple plot objects with a single plot command, the handle returned by plot is actually an array of plot objects (one for each plot).
plots = plot(rand(2));
size(plots)
1 2
Because of this, you cannot simply assign another [2x2] matrix to the XData.
set(plots, 'XData', rand(2))
You could pass a cell array of new XData to the plots via the following syntax. This is only really convenient if you already have your new values in a cell array.
set(plots, {'XData'}, {rand(1,2); rand(1,2)})
The other options is to update each plot object individually with the new values. As far as doing this quickly, there really isn't much of a performance hit by not setting them all at once, because they will not actually be rendered until MATLAB is idle or you explicitly call drawnow.
X = rand(2);
Y = rand(2);
for k = 1:numel(plots)
set(plots(k), 'XData', X(k,:), 'YData', Y(k,:))
end
% Force the rendering *after* you update all data
drawnow
If you really want to use the XDataSource and YDataSource method that you have shown, you can actually do this, but you would need to specify a unique data source for each plot object.
% Do this when you create the plots
for k = 1:numel(plots)
set(plots(k), 'XDataSource', sprintf('X(%d,:)', k), ...
'YDataSource', sprintf('Y(%d,:)', k))
end
% Now update the plot data
X = rand(2);
Y = rand(2);
refreshdata(plots)
You can use drawnow:
%Creation of the vectors
x = 1:100;
y = rand(1,100);
%1st plot
h = plot(x,y);
pause(2);
%update y
y = rand(1,100);
set(h,'YData',y)
%update the plot.
drawnow
I was wondering if anyone knew how to do an animation plot of
x = (dataset of 1000 points)
y = (dataset of 1000 points)
plot(x,y)
big problem is these are datasets that i am trying to plot , or x,y coordinates as opposed to a function which I would know how to plot via an animation.
I tried to do frames in a for loop but it gave me dots and didn't join them in a line graph so I couldn't really watch the path being traced out.
code I used was
for i = 1:length(DATASET1)
pause(0.1)
plot(DATASET1(i),DATASET2(i))
draw on
end
If what you want is for the plot to "grow" point by point: the easiest way is to create an empty plot and then update its XData and YData properties at each iteration:
h = plot(NaN,NaN); %// initiallize plot. Get a handle to graphic object
axis([min(DATASET1) max(DATASET1) min(DATASET2) max(DATASET2)]); %// freeze axes
%// to their final size, to prevent Matlab from rescaling them dynamically
for ii = 1:length(DATASET1)
pause(0.01)
set(h, 'XData', DATASET1(1:ii), 'YData', DATASET2(1:ii));
drawnow %// you can probably remove this line, as pause already calls drawnow
end
Here's an example1 obtained with DATASET1 = 1:100; DATASET2 = sin((1:100)/6);
1 In case someone's interested, the figure is an animated gif which can be created by adding the following code (taken from here) within the loop, after the drawnow line:
frame = getframe(1);
im = frame2im(frame);
[imind,cm] = rgb2ind(im,256);
if ii == 1;
imwrite(imind,cm,filename,'gif','Loopcount',inf);
else
imwrite(imind,cm,filename,'gif','WriteMode','append');
end
Looks like you were close. Not sure draw on is any command though.
See if the code here inspires you to solve your case -
%// Sample x and y values assumed for demo.
x = 1:1000;
y = x.^2;
%// Plot starts here
figure,hold on
%// Set x and y limits of the plot
xlim([min(x(:)) max(x(:))])
ylim([min(y(:)) max(y(:))])
%// Plot point by point
for k = 1:numel(x)
plot(x(k),y(k),'-') %// Choose your own marker here
%// MATLAB pauses for 0.001 sec before moving on to execue the next
%%// instruction and thus creating animation effect
pause(0.001);
end
Since R2014b, you can work with annimatedline object (doc and how-to) that is meant to handle animated graphs pretty well. Basically, the annimatedline object has a addpoints function that adds new points to the line without having to redefine the existing points, along with a clearpoints function that clears lines for more complex animations.
Here is an example:
h = animatedline;
axis([0,4*pi,-1,1])
x = linspace(0,4*pi,1000);
y = sin(x);
for k = 1:length(x)
addpoints(h,x(k),y(k));
drawnow
end