plot time in HH:MM ix x axis

Hi, I have 16000 sampled data. I want to plot it vs time in HH:mm format (ex 15:33)

I know when the first data point was taken (12:33:00) and I sampled 1 per 10 seconds.

I cant figure out how to do this

Answer 1

[Ankit]

You need to change the format using datetick.

date={'15:10:34.600 AM 2/26/2017','15:20:34.700 AM 2/26/2017','15:30:34.800 AM 2/26/2017','15:40:34.900 AM 2/26/2017'};
timeFormat='HH:MM:SS.FFF AM mm/dd/yyyy';
xdatenum=datenum(date,timeFormat);
data=0:3;
plot(xdatenum,data,'*');
datetick('x','HH:MM');

[Ron Amar]

oh great thanks.

just 1 more question - this 'date' string vector I have to manually make? how do i genarate it?

[Ankit]

You can use datetime Arrays to represent dates and times. I edited the code a bit as per your request. Please refer this link to know more: Arrays that represent points in time - MATLAB - MathWorks Deutschland

t = datetime(0,0,0,15,33,1:100:5000);  % Y,M,D,HH,MM,SS, sampling 1 per 10s
x = randn(50, 1);
plot(t, x)
datetick('x', 'HH:MM')
xlim(t([1 end]))

[Ron Amar]

you're the best Ankit thank you so much!

[Ankit]

Hi @Ron Amar if it works could you please accept the answer! Thanks

[Steven Lord]

Instead of using a datetime, which requires date information, I'd use a duration array to plot this data.

t = duration(15, 33, 1:100:5000);
x = randn(50, 1);
plot(t, x)
xlim(t([1 end]))

Change the Format of the duration array to change how it is displayed as labels.

t = duration(15, 33, 1:100:5000, 'Format', 'hh:mm'); % no second data
x = randn(50, 1);
plot(t, x)
xlim(t([1 end]))

[Ankit]

@Steven Lord thanks for your suggestion. now I know one more way to achieve this :)