I have a 2D plot with many data elements on it covering a extensive area. Although all the data is necessary, I am usually interested on a small element of the plot.
I would like to programmatically focus the view on that element of interest, while allowing to use the zoom tool ((-) in the GUI) to fastly go back to a wider perspective.
It is easy to use set(gca, 'xlim', [limitsXOfSmallElement]) and set(gca, 'ylim', [limitsYOfSmallElement]) to set axis limits so that the small element is in focus, but this makes impossible to use the GUI (-) zoom tool to go back to the general view without manually resetting back axis limits to original values.
My intuition is that this could be solved by controlling camera properties (CameraPosition, CameraTarget and/or CameraViewAngle), but when I apply them, posterior uses of the GUI zoom tool have weird effects on the axis, as changing its position and size on the figure.
Is there a good method for setting the fragment of the 2D canvas that is displayed in the axis?
Consider the following example:
function example_zoom
%# some plot
plot(1:10)
hAx = gca;
%# save original axis limits
setappdata(hAx, 'limits',get(gca,{'XLim','YLim'}))
%# create custom toolbar button
[X,map] = imread(fullfile(toolboxdir('matlab'),'icons','view_zoom_out.gif'));
icon = ind2rgb(X,map);
uipushtool('CData',icon, 'ClickedCallback',{#click_cb,hAx});
%# zoom
uiwait(msgbox('Zooming now, click button to reset', 'modal'))
set(gca, 'XLim',[3 7], 'YLim',[2 9])
%zoom on
end
function click_cb(o,e, hAx)
%# restore original axis limits
limits = getappdata(hAx, 'limits');
set(hAx, 'XLim',limits{1}, 'YLim',limits{2})
end
The idea is to create your own toolbar button that restores the axis limits to their original values.
Related
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
I am trying to line up a plot of a signal with an image where the image has a colorbar. The colorbar causes the axes to be offset horizontally.
My intuitive approach would be to fix the size of figures to something, like in Gnuplot with papersize. However, not sure which would be the best fit here.
To Adjust Scaling to Square in Full Screen Mode of Matlab?
I want to maintain the relations between the two figures. I cannot use squareform in the first figure for some reason, while I can in the latter figure.
Code
figure
ax2=subplot(2,2,2);
plot(mat2gray(pdist(data, 'correlation')));
title('Corr pdist');
cbar2 = colorbar(ax2);
xlim([0 size(mat2gray(pdist(data, 'correlation')),2)]);
set(cbar2, 'Visible', 'off');
ax4=subplot(2,2,4);
imshow(squareform( mat2gray(pdist(data, 'correlation')), 'tomatrix') );
colormap('parula'); colorbar;
title('Square Corr pdist');
Wrong Scaling in Output when Full Screen Mode of Matlab where you see the colorbar method is not sufficient for holding relations as proposed in the answer here about How to Control Relative Size of Figures with Colorbar in Matlab?
Right Scaling in Output when Default View
How can you maintain the square view of figures in the Full Screen Mode of Matlab?
I would simply create a colorbar for the top axes as well and set the visibility to off.
figure;
ax1 = subplot(2,1,1);
ax2 = subplot(2,1,2);
cbar1 = colorbar(ax1);
cbar2 = colorbar(ax2);
set(cbar1, 'Visible', 'off')
The benefit here is that you will get consistent behavior when resizing the figures, etc. because the size and position of the two axes will be rendered in the same way.
The other thing you will need to remember is to keep the axes the same in all aspects. So for example if you have an image in the bottom axes (using imshow), MATLAB by default sets the axes to a square. To get your top plot to also be square you will need to use axis square. Then they will continue to line up.
axis(ax1, 'square')
I am creating a candlestick chart representing stock prices. Once created, I want to add green circle showing where/when I am buying the stock.
hold on;
candle(myData.High, myData.Low, myData.Close, myData.Open, '', myData.Date, 'dd/mm/yy');
m = plot(myExecutionTable.BuyDate,myExecutionTable.BuyPrice,'og')
uistack(m)
hold off;
The problem is that if myExecutionTable.BuyPrice has a value between the Open and Close, the circle is not showing up. I guess it is hidden under the candlestick. Hence I tried to use uistack but without success. When I change to
plot(myExecutionTable.BuyDate,myExecutionTable.BuyPrice+100,'og')
the green circle then appears (above the candlestick)
Thanks,
Serge
The easiest way to make sure one graphics object is on top of another (and not below), is to plot it later.
If for some reason you can't do it this way, you can also manipulate the order of the child objects of the axes:
h = get(gca, 'Children');
returns a vector of graphics handles. Exchange handles between positions in this vector (higher index means higher on top), and then write it back using
set(gca, 'Children', h)
I'd like to zoom in on a plot using a script. I'm only interested in horizontally constrained zooming. So I'd like to do something like
p = plot(myData);
z = zoom;
set(z, 'ZoomInToPoints' , [50 100]);
or
p = plot(myData);
myZoom([50, 100]);
So either of these functions would zoom into a plot like when you zoom in with the magnifying glass tool. I only specify two points because I only want to zoom horizontally.
Note, I've already tried to use xlim for this. While it works, it doesn't let me use the command text on my plots, which I need.
Calls to text will fix the text at a specific set of coordinates on the graph. Have you tried updating these after calling xlim?
EDIT: You can always adjust the text position:
x=1:.1:10;
y=sin(.1*x);
plot(x,y)
text(6,.8,'test') %#Sample figure
F=get(0,'children'); %#Figure handle
A=get(F,'Children'); %#Axes handle
T=findobj(A,'Type','text'); %# Text handle
oldxlim=xlim; %#grab the original x limits before zoom
oldpos=get(T,'Position'); %#get the old text position
set(A,'xlim',[5 15]); %#Adjust axes
newxlim=xlim;
newpos=[(oldpos(1)-oldxlim(1))*(diff(newxlim))...
/(diff(oldxlim))+newxlim(1) oldpos(2:end)];
%#interpolate to place the text at the same spot in the axes
set(T,'Position',newpos) %#Finally reset the text position
Not pretty, but it should work. If you have more than one annotation per axes or axes per figure, you can always throw the above code in a loop.
What is the problem with text and xlim? Is this not the type of behavior you want?
plot(1:100,randn(100,1))
text(80,1.5,'text')
set(gca,'XLim',[70 100]) % notice that text stays at same point in "data space" but moves in "axis space"
text(80,1,'text2'); % new text appears in axis space as well
If I'm misunderstanding and you want text to appear at a specific point in your axis space (not the data space that text uses) regardless of how zoomed in you are, you can create another set of axes for your text:
inset_h = axes('position',[0.5 0.5 0.2 0.2])
set(inset_h,'Color','none'); axis off
text(0,0,'text')
How do you take one plot and place it in the corner (or anywhere for that matter) of another plot in MATLAB?
I have logarithmic data that has a large white space in the upper right-hand side of the plot. In the white space I would like to overlay a smaller plot containing a zoomed in version of the log plot in that white space (sort of like a magnified view).
Before you tell me it can't be done, I would like to mention that I have seen it in action. If my description is lacking, just let me know and I'll attempt to better describe it to you.
An example:
x = 1:20;
y = randn(size(x));
plot(x, y,'LineWidth',2)
xlabel('x'), ylabel('y'), title('Plot Title')
h = axes('Position', [.15 .65 .2 .2], 'Layer','top');
bar(x,y), title('Bar Title')
axis(h, 'off', 'tight')
You can use axes properties 'position' and 'units' and make them overly. Pay attention to create small axes after big one or use uistack() function so that big does not hide small one.
What you can not do is to make an axes child of another one (like Mathworks do with legend). But you do not need it anyway.
For the second plot you have to use axes and line instead of plot and hold on.
Units as 'normalized' (which is default) allows uniform resizable look when parent figure is being resized (e.g. manually maximized).