Set tick label of the color bar with dates in the format yyyy-MM-dd HH:mm:ss.

Dear all,

I have a dataset (x,y,z) that I am plotting over time. The time column was originally in the following format 'yyyy-mm-dd HH:mm:ss'.

For the plot, I converted it to decimal year, and this is the label that appear in the colorbar. But I would like to have the colorbar label in the format 'yyyy-mm-dd HH:mm:ss'.

I tried something similar to this:

hcb.TickLabels = datestr(dates, 'yyyy-MM-dd HH:mm:ss');

but the label are not the corrected one (see figure).

Has someone a suggestions?

Thanks to all the will reply,

Chiara

[Yukthi S]

Hi @Chiara Lanzi,

The original and desired format looks the same to me, 'yyyy-mm-dd HH:mm:ss'. Can you tell me what is that you want to achieve?

[Chiara Lanzi]

Dear Yukthi S,

thanks for your message.

The problem is that what I got as a label something like 2021-49-20 instead of the correct month and day (in this case 09-18). The year is correct but the months and day not.

Chiara

[Steven Lord]

You used "mm" twice in the format, and that is interpreted as the minutes data. If you were using datetime MATLAB should have warned you about this as shown below. You want to use MM or MMM for months.

dt = datetime('now')

dt = datetime
   11-Dec-2024 16:14:53

F = dt.Format

F = 'dd-MMM-uuuu HH:mm:ss'

dt.Format = replace(F, 'MMM', 'MM') % 2-digit month instead of short name

dt = datetime
   11-12-2024 16:14:53

dt.Format = replace(F, 'MMM', 'mm') % minutes in place of months

Warning: The format 'dd-mm-uuuu HH:mm:ss' contains a field for minute (m) in what appears to be a date portion. You might have intended to use the symbol for month (M) rather than for minute (m). See the datetime.Format property for a complete description of the identifiers used in datetime formats.

dt = datetime
   11-14-2024 16:14:53

[Chiara Lanzi]

Dear Steven Lord,

Thanks for pointing this out, I have to admit I did not see hta tI was using twice "mm", my bad.

Chiara

Answer 1

[Cris LaPierre]

I'm not sure how you created the dates variable used to set the tick labels. It can be difficult to convert decimal years back into a date string since you often lose the precision needed to accurately reconstruct the datetime.

Here's an example of how you could avoid that by manually creating the colorbar ticks and labels.

Z = peaks;
times = datetime('now','Format','yyyy-MM-dd HH:mm:ss') + days(Z);
dyears = decyear(times)

dyears = 49×49

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surf(dyears)
hcb = colorbar;

% manually set the colorbar tick locations and labels
start = min(times(:));
stop = max(times(:));
dticks = linspace(start,stop,10);
hcb.Ticks = decyear(dticks);
hcb.TickLabels = string(dticks);
ax = gca;
ax.OuterPosition(3) = 0.8;

[Chiara Lanzi]

Dear Cris LaPierre,

thanks for your time in answering my question. I foolowe your suggestions and it worked quite well. Thnak you for your help.

Chiara