How to plot with YYYYMM date format on x-axis?

LS,

I would like to plot some data with dates on the horizontal axis. The dates are in YYYYMM format.

When I plot the data set, there is a small horizontal space between e.g. 200911 and 200912. However, there is a large horizontal space between e.g. 200912 and 201001. It is clear why this happens...

Does someone probably have a solution for this issue? Should i convert the YYYYMM format to a date format which matlab understands? How? Or does an option for equidistantial horizontal spacing in graphs exists?

Your help would be very much appreciated.

Best regards,

Frits

Answer 1

[Jiro Doke]

This would convert your dates in YYYYMM format to serial dates which would have the correct intervals between the dates.

x = [200911 200912 201001 201002];
serialDates = datenum(num2str(x(:)), 'yyyymm')

Confirm with this:

datestr(serialDates)

[the cyclist]

If you use this approach, then you can use the "datetick" command (which effectively converts datenum-type numeric dates to calendar dates) to create the labels.

Answer 2

[the cyclist]

Yes, you'll need to convert those integers, which are not regular, into something that just count the months. Something like

year = floor(yyyymm/100);
month = yyyymm - 100*year;

Then count the months from some reference year/month.

[Frits]

Thanks for your answer.

How would you label the horizontal axis in order to show year and month?

[the cyclist]

You could do something like this:

yyyymmVector

set(gca,'XTick',yyyymmVector)

set(gca,'XTickLabel',num2str(yyyymmVector))

But see also Jiro's solution.

[the cyclist]

In the above comment, "yyyymmVector" was meant to represent your vector of integer dates.

Answer 3

[Tiago Dias]

Hello, i have a question, i got a table, the 1st column i have my time series, DD-MM-YYYY HH:MM:SS and on the others I got my variables.

I want to plot the time vs the variables

time = data(:,1); variables = data(:,2:end);

when i make plot(time,variables) i get an error

how can i fix it besides changing the data to 1 to 300