How to label the x-axis of a time series with the years?

I have a time series that gives data every hour from 1979 January 1st 00:00 am to 2021 March 11th 22:00 pm. So, I have a time series that has 369886 elements in total and it's a row vector. For example, use x= rand(369886,1). How do you show the years on the x axis (using xlabel)?

(i.e, 1979,1980,...,2021 on the x axis taking into account the leap years etc)

I'd highly appreciate an example if it's possible

Answer 1

[Chien-Han Su]

In my opinion, you just need to find the index of data corresponding to each year's Jan 1st 0:00 am and label it. My example is as follows

% get data
x=log10(1:369886);

% parameters for the process 
listLeapYear1970to2030 = ...
    [1972 ,1976, 1980, 1984, 1988, ...
    1992, 1996, 2000,2004, 2008, ...
    2012, 2016, 2020, 2024, 2028];
hour4Normal = 24*365;
hour4Leap = 24*366;
yearFirst = 1979;
hour4FirstYear = hour4Normal;


% start labeling 
labelYear = zeros(size(x));
ind4YearStart = [];
pivot = 0;
yearCurrent = yearFirst  
while pivot+1 <= numel(x)
    ind4YearStart = [ind4YearStart, (pivot+1)]; 
    labelYear(pivot+1) = yearCurrent;
    if ~ismember(yearCurrent, listLeapYear1970to2030) % normal year
        pivot = pivot + hour4Normal;
    else % l
        pivot = pivot + hour4Leap;
    end
    yearCurrent = yearCurrent+1;
end
yearLast = yearCurrent;

% show data
yearSeparation2Show = 4;
plot(x)
xticks(ind4YearStart(1:yearSeparation2Show:end))
xticklabels(num2str((yearFirst:yearSeparation2Show:yearLast)'))
axis([-inf inf -inf inf])

and the result is like

※Since the data starts also from Jan 1st 0:00 in your case which make thing easier by letting

hour4FirstYear = hour4Normal;

if not, you can modify hour4FirstYear to any other value according to your situation.

※To make the x-axis more easy to read, I only show the year label every 4 years by letting

yearSeparation2Show = 4;

You can adjust the separation when you need

[tng]

Woah this is longer than I expected but thank you so much, really appreciate it! I thought there was a shorter way with datenum or datestick but I kept getting errors. This works anyway, so should be fine. Thanks again.