Upper limit on the number of UIAxes children allowed

I am plotting orbital data, using plot3 to progressively lengthen the orbital track of a spacecraft.

plot3(earthMoon.UIAxes, x,y,z,"w');

Each time I do this, another "Children' is added to the UIAxes instance. Eventually, when the number of children approaches 200 or so, the graphical object management becomes unwieldy and my GUI stops responding to button pushes; even the Matlab STOP and CONTINUE buttons fail to respond.

I found a similar question and answer here:

https://www.mathworks.com/matlabcentral/answers/433845-maximum-number-of-uiaxes-in-app-designer-2017b?s_tid=prof_contriblnk

Is there a better way to manage the Children? I have tried thinning out my track data to reducte the number of points, but that results in jerky updates that don't align with the orbital state. I have also looked at using splines, but I will still need to limit the number of current track points to something under 200.

I have another app for displaying radar data where I progressively delete the oldest children in the UIApp, so I never have more than about 50. That works well, but for orbital data I would like to display the whole trajectory from launch to current time. It appears I can't have it both ways.

[Kurt]

This is precisely the same problem I am running into with rendering 2D graphics with plot(). It is especially true when you use scatter plots, which quickly add reams of children to the axes object. Eventuallly the whole view grinds to a halt.

[Walter Roberson]

The upper limit on the number of uiaxes children exceeds 2^20.

(That doesn't mean that you get good performance if you have that many!)

[dpb]

"...when you use scatter plots, which quickly add reams of children to the axes object"

You can avoid scatter by using

hL=plot(x,y,'o');

then follow the preceding advice to update the X|YData of the given line handle. There will have to be one line for each desired marker/color combination, however, since those properties are unique to the object handle.

I've not experimented with the animatedline with the idea of it being a scatter substitute so not positive about it with only the marker but I presume it will allow that...

[Walter Roberson]

plot() and scatter() scale at about the same rate, but plot() is a bit faster. See https://blogs.mathworks.com/graphics/2015/01/20/performance-scaling/

Answer 1

[Voss]

Consider updating the XData, YData, and ZData of an existing line, rather than creating a new line each time you want to add more data to the plot.

For that, you can use a line object (such as what plot3 creates), or you may find it convenient to use an animatedline object.

https://www.mathworks.com/help/matlab/ref/matlab.graphics.primitive.line-properties.html

https://www.mathworks.com/help/matlab/ref/matlab.graphics.animation.animatedline-properties.html

https://www.mathworks.com/help/matlab/ref/addpoints.html

[Kurt]

The animatedline approach worked. Thanks!

[Voss]

You're welcome!

Answer 2

[dpb]

Don't call plot3 (or friends) multiple times for such, update the data properties of the one having been called or use the animatedline instead.