converting from integer time to datetime in 3-hourly data
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I've tried everything I can think of to convert from integer time to datetime. Anyone have any intuitions or suggestions? Thanks!
time
Size: 13208x1
Dimensions: record
Datatype: double
Attributes:
standard_name = 'time'
long_name = 'Time'
units = 'hours since 1979-12-01 00'
time_calendar = 'gregorian'
start = '1979120100'
step = '3'
With having a time step of '3' I'm not sure how to apply the datetime function.
For reference:
>> time(1)
ans =
176064
6 个评论
Carrie Merritt
2020-12-1
My answer moved here:
X = {'1979120100', '1979120103', '1979120106'}
T = datetime(X,'InputFormat','yyyyMMddhh','Format','yyyy-MM-dd HH:mm')
result is:
T =
1×3 datetime array
1979-12-01 00:00 1979-12-01 03:00 1979-12-01 06:00
Some calculation:
>> T(3)-T(1)
ans =
duration
06:00:00
Stephan
2020-12-1
Carries comment moved here:
Hi Stephan,
Thanks for the response. If you notice, I referenced the first time integer (e.g., time(1) = 176064). The method you have suggested assumes I already have a time vector in the 'yyyyMMddHH' format. Which I do not. It is what I need though.
I'm not sure what kind of time units I'm working with aside from what information I have in the netCDF file.
Stephan
2020-12-1
I see, can you attach the data object you have there?
Carries comment moved here:
Please see attached. There isn't anything on the script aside from my numerous failed attempts at trying to make this work. All I'm trying to do is read the time in and convert it from its original netCDF format to a date/time format.
Walter Roberson
2020-12-1
Is it possible that the first time should be 05-Jun-1982 ?
采纳的回答
Heres an approach:
I believe the idea behind this:
is that the integer values start counting by
1979-12-01 00:00 --> 0
1979-12-01 03:00 --> 3
1979-12-01 06:00 --> 6
If this assumption would be correct:
data = ncread('EasterlyOneYear850.nc','time');
time_new = datetime('1979-12-01 00:00') + hours(data);
Should give you the correct time values in your data:
time_new(1:3)
gives then:
ans =
3×1 datetime array
01-Jan-2000 00:00:00
01-Jan-2000 03:00:00
01-Jan-2000 06:00:00
So we end up that your data could have started exactly by millenium and ends here:
>> time_new(end)
ans =
datetime
31-Dec-2000 21:00:00
which is the last possible value in the year 2000, since the next one would be in the year 2001.
Can this be correct?
3 个评论
Walter Roberson
2020-12-2
In https://www.mathworks.com/matlabcentral/answers/671843-converting-from-integer-time-to-datetime-in-3-hourly-data#comment_1175298 they say that the expected output is like 1980-12-1-0 .
I cannot make the numbers work out to that unless the first date should instead be 1982-06-05 (05-Jun-1982)
Stephan
2020-12-3
Ok, i missed that.
Carrie Merritt
2021-4-13
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