converting from integer time to datetime in 3-hourly data

Question

Carrie Merritt 2020-12-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/671843-converting-from-integer-time-to-datetime-in-3-hourly-data

评论： Carrie Merritt 2021-4-13

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
显示 4更早的评论隐藏 4更早的评论

Stephan 2020-12-1

编辑：Stephan 2020-12-1

EasterlyOneYear850.zip

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 ?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Stephan 2020-12-2

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/671843-converting-from-integer-time-to-datetime-in-3-hourly-data#answer_562698

编辑：Stephan 2020-12-2

在 MATLAB Online 中打开

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
显示 1更早的评论隐藏 1更早的评论

Stephan 2020-12-3

Ok, i missed that.

Carrie Merritt 2021-4-13

So sorry I never followed up on this! Yes, so it turns out the starting time is 2000-01-01-00 and ending time is 2000-12-31-21. The issue was that I was under the assumption that my collaborator who gave me this tracking data/file, was using the full MERRA-2 period (starting in 1980). After confirming with her, this particular file was just for 2000. Yeesh. This is why attribute data is always important, right?! Thanks so much for the help on this and I will be sure to remember to come back to this answer if I ever run into the same issue without having access to author of the file. :)

请先登录，再进行评论。

converting from integer time to datetime in 3-hourly data

6 个评论
显示 4更早的评论隐藏 4更早的评论

采纳的回答

3 个评论
显示 1更早的评论隐藏 1更早的评论

更多回答（0 个）

另请参阅

类别

标签

Community Treasure Hunt

converting from integer time to datetime in 3-hourly data

6 个评论 显示 4更早的评论隐藏 4更早的评论

采纳的回答

3 个评论 显示 1更早的评论隐藏 1更早的评论

更多回答（0 个）

另请参阅

类别

标签

Community Treasure Hunt

6 个评论
显示 4更早的评论隐藏 4更早的评论

3 个评论
显示 1更早的评论隐藏 1更早的评论