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How to add a datetime array to addpoints for an animated line plot?

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Hi,
Let's say I have a datetime & temperature arrays as following:
Xdata Ydata
'05:00:00.048' 41
'05:00:00.052' 42
'05:00:00.056' 40.5
'05:00:00.060' 43
'05:00:00.064' 44
'05:00:00.068' 45
'05:00:00.072' 45.5
'05:00:00.076' 46
'05:00:00.080' 47
'05:00:00.084' 47.5
'05:00:00.088' 48
I would like to plot an animation line using addpoints. "addpoints" needs Xdata to be a double but I need to plot it as a datetime object.
Help me understand if there's another way around this.
Thanks,
Sun

Accepted Answer

Walter Roberson
Walter Roberson on 2 Oct 2019
Unfortunately, animatedLine only permits double()
There are some obscure circumstances in plotting under which datetime objects will automatically be converted to doubles, but this is not one of those circumstances. :(
  2 Comments
Eric Prandovsky
Eric Prandovsky on 9 Feb 2023
Edited: Eric Prandovsky on 9 Feb 2023
Previous examples show converting to serial date number using datenum
datenum(datetime)
ans = 7.3893e+05
But the datenum documentation says it's no longer recommended, any idea what the new suggested method is?
Noah Prisament
Noah Prisament on 7 Jun 2023
The "animatedline" now supports "datetime" values natively, so this is the new suggested method. This will also show the proper ruler on each axis. See my answer below for example syntax.

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More Answers (2)

Ajay Kumar
Ajay Kumar on 2 Oct 2019
Try this:
Convert the datetime values to numbers using datenum.
Fetch these datenum values as x parameter to addpoints.
While plotting convert these datenum values to datetime again using datetime and 'ConvertFrom'.
I hope it works.
  1 Comment
Sun
Sun on 2 Oct 2019
Edited: Walter Roberson on 2 Oct 2019
Kumar,
Thanks for the response. addpoints itself plots the data. I am not able to do addpoints first and then convert the data for sake of a plot.
This is what I used:
h = animatedline('Marker','o');
addpoints(h,Xdata,Ydata);
This is the error: Error using matlab.graphics.animation.AnimatedLine/addpoints Invalid type for argument X. Type should be double.
I can try
Xdata_num = datenum(Xdata);
addpoints(h,Xdata_num,Ydata);
But plotting Xdata_num doesn't help as data constitutes to date which is the same for all time points.

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Noah Prisament
Noah Prisament on 7 Jun 2023
The "animatedline" now supports all numeric datatypes as well as datetimes and durations for all axes as of R2023a!
In order to plot your data on an "animatedline" you can now utilize the following example:
h = animatedline(NaT, NaN);
addpoints(h, Xdata, Ydata);
or to initialize the "animatedline" with data:
h = animatedline(Xdata, Ydata);

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