Plot within a plot in MATLAB - matlab

I am trying to create a smaller plot within a plot in MATLAB, for example like the image of this MATLAB File Exchange Upload.
There, two figures are created and then both of them are plotted in one figure.
My problem however is that I already have two MATLAB figures from earlier simulations and I need to embed one figure into the other one, i.e., one would be small and the other plot would be big but in the same graph. Could someone suggest an easy way to do this?

This can be done using the copyobj function. You'll need to copy the Axes object from one figure to the other:
f(1) = openfig('fig1.fig');
f(2) = openfig('fig2.fig');
ax(1) = get(f(1),'CurrentAxes'); % Save first axes handle
ax(2) = copyobj(get(f(2),'CurrentAxes'),f(1)); % Copy axes and save handle
Then you can move and resize both axes as you like, e.g.
set(ax(2),'Position', [0.6, 0.6, 0.2, 0.2]);

Related

How to update a scatter3 plot (in a loop) in Matlab

Quite a simple question but just couldn't find the answer online... I want to visualise a point cloud gathered from a lidar. I can plot the individual frames but wanted to loop them to create a "animation". I know how to do it for normal plots with drawnow but can't get it working with a scatter3. If I simply call scatter3 again like I have done in the commented code then the frame that I am viewing in the scatter plot jumps around with every update (Very uncomfortable). How do i get the scatter3 plot to update to the new points without changing the UI of the scatter ie. Still be able to pan and zoom around the visualised point cloud while it loops through.
EDIT: The file is a rosbag file, I cannot attach it because it is 170MB. The problem doesn't happen when using scatter3 in a loop with a normal array seems to be something with using scatter3 to call a PointCloud2 type file using frame = readMessages(rawBag, i).
EDIT: The problem does not seem to be with the axis limits but rather with the view of the axis within the figure window. When the scatter is initialised it is viewed with the positive x to the right side, positive y out of the screen and positive z upwards, as shown in view 1. Then after a short while it jumps to the second view, where the axis have changed, positive x is now out of the screen, positive y to the right and positive z upwards (both views shown in figures). This makes it not possible to view in a loop as it is constantly switching. So basically how to update the plot without calling scatter3(pointCloudData)?
rawBag = rosbag('jackwalking.bag');
frame = readMessages(rawBag, 1);
scatter3(frame{1});
hold on
for i = 1:length(readMessages(rawBag))
disp(i)
frame = readMessages(rawBag, i);
% UPDATE the 3D Scatter %
% drawnow does not work?
% Currently using:
scatter3(frame{1})
pause(.01)
end
The trick is to not use functions such as scatter or plot in an animation, but instead modify the data in the plot that is already there. These functions always reset axes properties, which is why you see the view reset. When modifying the existing plot, the axes are not affected.
The function scatter3 (as do all plotting functions) returns a handle to the graphics object that renders the plot. In the case of scatter3, this handle has three properties of interest here: XData, YData, and ZData. You can update these properties to change the location of the points:
N = 100;
data = randn(N,3) * 40;
h = scatter3(data(:,1),data(:,2),data(:,3));
for ii = 1:500
data = data + randn(N,3);
set(h,'XData',data(:,1),'YData',data(:,2),'ZData',data(:,3));
drawnow
pause(1/5)
end
The new data can be totally different too, it doesn't even need to contain the same number of points.
But when modifying these three properties, you will see the XLim, YLim and ZLim properties of the axes change. That is, the axes will rescale to accommodate all the data. If you need to prevent this, set the axes' XLimMode, YLimMode and ZLimMode to 'manual':
set(gca,'XLimMode','manual','YLimMode','manual','ZLimMode','manual')
When manually setting the limits, the limit mode is always set to manual.
As far as I understood what you describe as "plots jumpying around", the reason for this are the automatically adjusted x,y,z limits of the scatter3 plot. You can change the XLimMode, YLimMode, ZLimMode behaviour to manual to force the axis to stay fixed. You have to provide initial axes limits, though.
% Mock data, since you haven't provided a data sample
x = randn(200,50);
y = randn(200,50);
z = randn(200,50);
% Plot first frame before loop
HS = scatter3(x(:,1), y(:,1), z(:,1));
hold on
% Provide initial axes limits (adjust to your data)
xlim([-5,5])
ylim([-5,5])
zlim([-5,5])
% Set 'LimModes' to 'manual' to prevent auto resaling of the plot
set(gca, 'XLimMode', 'manual', 'YLimMode', 'manual', 'ZLimMode', 'manual')
for i=2:len(x,2)
scatter3(x(:,i), y(:,i), z(:,i))
pause(1)
end
This yields an "animation" of plots, where you can pan and zoom into the data while continuous points are added in the loop

Two saved figures, want them to show in a single graph in MATLAB

Let's say I have two figures stored in separate files A.fig and B.fig which contain two separate plots. Is there a way to load A.fig and then do something like hold on and then load B.fig in the figure created for A.fig so that I have both plots in the same axes?
I think the question is not really a duplicate of this one. The OP does not ask for a way to extract the data but for a way to combine the two stored figures. Admittedly, he could extract the data and plot it again. But there is a more elegant solution...
The actual plots are children of axes which is a child of figure. Therefore you can achieve what you want by copying the children of the second axes into the first axes with copyobj. Before that, load the figures with openfig. This method has the advantage to copy different types of 'plots' (line, area, ...).
The code to copy from B.fig to A.fig is as follows and works starting from R2014b:
fig1 = openfig('A');
fig2 = openfig('B', 'invisible');
copyobj(fig2.Children.Children, fig1.Children);
If you have a Matlab version prior to R2014b, you need to use the set and get functions since you cannot use .-notation. More information can be found here. You can either use gca to get the current axes after loading the figure like this:
fig1 = openfig('A');
ax1 = gca;
fig2 = openfig('B', 'invisible');
ax2 = gca;
copyobj(get(ax2,'children'), ax1);
... or get them manually from the figure-handle like this:
fig1 = openfig('A');
fig2 = openfig('B', 'invisible');
copyobj(get(get(fig2,'children'),'children'), get(fig1,'children'));
The following script creates two figures and then applies the above code to combine them.
If you are have Matlab version R2013b or higher, replace hgsave with savefig as suggested in the documentation.
%% create two figure files
x = linspace(0,2*pi,100);
figure; hold on;
plot(x,sin(x),'b');
area(x,0.5*sin(x));
set(gca,'xlim',[0,2*pi]);
hgsave('A');
figure; hold on;
plot(x,cos(x),'r');
area(x,0.5*cos(x),'FaceColor','r');
hgsave('B');
%% clear and close all
clear;
close all;
%% copy process
fig1 = openfig('A');
fig2 = openfig('B', 'invisible');
copyobj(get(get(fig2,'children'),'children'), get(fig1,'children'));
close(fig2);
This gives the following result if manually combined in subplots:

How to specify the axis size when plotting figures in Matlab?

Suppose that I have 2 figures in MATLAB both of which plot data of size (512x512), however one figure is being plotted by an external program which is sets the axis parameters. The other is being plotted by me (using imagesc). Currently the figures, or rather, the axes are different sizes and my question is, how do I make them equal?.
The reason for my question, is that I would like to export them to pdf format for inclusion in a latex document, and I would like to have them be the same size without further processing.
Thanks in Advance, N
Edit: link to figures
figure 1: (big)
link to smaller figure (i.e. the one whose properties I would like to copy and apply to figure 1)
For this purpose use linkaxes():
% Load some data included with MATLAB
load clown
% Plot a histogram in the first subplot
figure
ax(1) = subplot(211);
hist(X(:),100)
% Create second subplot
ax(2) = subplot(212);
Now link the axes of the two subplots:
linkaxes(ax)
By plotting on the second subplot, the first one will adapt
imagesc(X)
First, you have the following:
Then:
Extending the example to images only:
load clown
figure
imagesc(X)
h(1) = gca;
I = imread('eight.tif');
figure
imagesc(I)
h(2) = gca;
Note that the configurations of the the first handle prevail:
linkaxes(h)
1.Get the handle of your figure and the axes, like this:
%perhaps the easiest way, if you have just this one figure:
myFigHandle=gcf;
myAxHandle=gca;
%if not possible, you have to search for the handles:
myFigHandle=findobj('PropertyName',PropertyValue,...)
%you have to know some property to identify it of course...
%same for the axes!
2.Set the properties, like this:
%set units to pixels (or whatever you prefer to make it easier to compare to the other plot)
set(myFigHandle, 'Units','pixels')
set(myAxHandle, 'Units','pixels')
%set the size:
set(myFigHandle,'Position',[x_0 y_0 width height]) %coordinates on screen!
%set the size of the axes:
set(myAxHandle,'Position',[x_0 y_0 width height]) %coordinates within the figure!
Ok, based on the answer of #Lucius Domitius Ahenoba here is what I came up with:
hgload('fig1.fig'); % figure whose axis properties I would like to copy
hgload('fig2.fig');
figHandles = get(0,'Children');
figHandles = sort(figHandles,1);
ax(1) = findobj(figHandles(1),'type','axes','-not','Tag','legend','-not','Tag','Colorbar');
ax(2) = findobj(figHandles(2),'type','axes','-not','Tag','legend','-not','Tag','Colorbar');
screen_pos1 = get(figHandles(1),'Position');
axis_pos1 = get(ax(1),'Position');
set(figHandles(2),'Position',screen_pos1);
set(ax(2),'Position',axis_pos1);
This is the 'before' result:
and this is the 'after' result:
Almost correct, except that the aspect ratios are still off. Does anybody know how to equalize everything related to the axes? (I realize that I'm not supposed to ask questions when posting answers, however adding the above as a comment was proving a little unwieldy!)

How to plot graphs above each other in Matlab?

I want to plot two (or more) graphs in Matlab. I want them to be aligned one above the second one above the third and so on. However subplot is not the case for me. I also don't want them both to be on the same graph in different colors, just to be one above the other. Is it possible? I'm searching for such a command but without any success.
Thanks in advance for hints!
If what you mean by "one above the other" is one "on top of another" then I think what You need to use is the axes command. Having said that, in order to have your plot be readable, I think more than two scales in the same plot makes it pretty hard to read.
This Matlab's help page shows you how to do it, the gist of it is shown in the following script:
y2 = 1000.*rand(100,1);
x2 = 0:99;
% Plot the first data set
hl1 = line(x1,y1,'Color','r');
% Get the axes and configure it
ax1 = gca;
set(ax1,'XColor','r','YColor','r')
%Create the new axes
ax2 = axes('Position',get(ax1,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
% Plot the second data set with the new axes
hl2 = line(x2,y2,'Color','k','Parent',ax2);
The above script creates the following plot with one set of axes in red and another in black.
Hope this helps.

MATLAB - How to zoom subplots together?

I have multiple subplots in one figure. The X axis of each plot is the same variable (time). The Y axis on each plot is different (both in what it represents and the magnitude of the data).
I would like a way to zoom in on the time scale on all plots simultaneously. Ideally by using the rectangle zoom tool on one of the plots, and having the other plots change their X limits accordingly. The Y limits should remained unchanged for all of this. Auto fitting the data to fill the plot in the Y direction is acceptable.
(This question is almost identical to Stack Overflow question one Matplotlib/Pyplot: How to zoom subplots together? (except for MATLAB))
Use the built-in linkaxes function as follows:
linkaxes([hAxes1,hAxes2,hAxes3], 'x');
For more advanced linking (not just the x or y axes), use the built-in linkprop function
Use linkaxes as Yair and Amro already suggested. Following is a quick example for your case
ha(1) = subplot(2,1,1); % get the axes handle when you create the subplot
plot([1:10]); % Plot random stuff here as an example
ha(2) = subplot(2,1,2); % get the axes handle when you create the subplot
plot([1:10]+10); % Plot random stuff here as an example
linkaxes(ha, 'x'); % Link all axes in x
You should be able to zoom in all the subplots simultaneously
If there are many subplots, and collecting their axes handle one by one does not seem a clever way to do the job, you can find all the axes handle in the given figure handle by the following commands
figure_handle = figure;
subplot(2,1,1);
plot([1:10]);
subplot(2,1,2);
plot([1:10]+10);
% find all axes handle of type 'axes' and empty tag
all_ha = findobj( figure_handle, 'type', 'axes', 'tag', '' );
linkaxes( all_ha, 'x' );
The first line finds all the objects under figure_handle of type "axes" and empty tag (''). The condition of the empty tag is to exclude the axe handles of legends, whose tag will be legend.
There might be other axes objects in your figure if it's more than just a simple plot. In such case, you need to add more conditions to identify the axes handles of the plots you are interested in.
To link a pair of figures with linkaxes use:
figure;imagesc(data1);
f1h=findobj(gcf,,’type’,’axes’)
figure;imagesc(data2);
f2h=findobj(gcf,,’type’,’axes’)
linkaxes([f1h,f2h],’xy’)