Plotting a year by hour

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Claire
Claire on 19 Feb 2011
I'm attempting to plot a year by date and hour. Someone suggested the following code:
D = datevec(datenum(1992,1,1:1/24:366));
which produces a years worth of data plus one hour, so I've got 01-01-1992, 0:00:00 to 31-12-1992 0:00:00. So I've got 8761 rows of data for my hours, but only 8760 rows of input data. If anyone can point me in the right direction that would be great. Thank you.

Accepted Answer

Matt Fig
Matt Fig on 19 Feb 2011
Also, you realize 1992 was a leap year? Is that the year your data was taken? If it is for a generic year, why not use:
D2 = datevec(datenum(1993,1,1:1/24:365+23/24)); % makes 8760 rows
  1 Comment
Claire
Claire on 22 Feb 2011
Thank you, that's great, much appreciated.

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More Answers (2)

Matt Tearle
Matt Tearle on 19 Feb 2011
So the issue is how to extract the first 8760 elements of a vector of 8761 points? That's easy enough:
plot(x(1:end-1),y)

Matt Tearle
Matt Tearle on 19 Feb 2011
If you're starting just with data and the knowledge that it was recorded hourly throughout a given year, why not just do something like:
t = datenum(yr,1,1) + (0:(length(x)-1))/24;
D = datevec(t);
Or, alternatively
tstart = datenum(yr,1,1);
tend = datenum(yr+1,1,1) - 1/24;
n = 24*(tend-tstart) + 1;
if n==length(x)
t = linspace(tstart,tend,n);
% etc
else
error('wrong number of data points')
end

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