Converting Unix timestamp to datetime NETCDF4

Question

In my NetCDF file I have a group 'vel' containing the variable 'time' that I am using as my X-Axis when plotting with matplotlib and numpy.

I would like the plot X axis as datetime (rather than Unix time), but am not having much success from other code examples. I am not sure if it is better to do it inline during the plot creation, or perform a function on the variable and create a new data item/variable. Also, the Unix time is not an integer (decimal seconds - see below example)

1,1665583266.0000
2,1665583266.0625
3,1665583266.1250
4,1665583266.1875
5,1665583266.2500
6,1665583266.3125
7,1665583266.3750
8,1665583266.4375
9,1665583266.5000
10,1665583266.5625

Tried using variations of datetime.datetime.fromtimestamp(YOUR_UNIX_TIMESTAMP)

But got errors as below:

Only length-1 arrays can be converted to Python scalars

Not seen any examples of doing time conversion on NetCDF dataset

This clearly works on a single data item as the following works as expected and returns todays date/time of 2022-12-22 13:23:35:

import datetime
 
unixToDatetime = datetime.datetime.fromtimestamp(1671715415) # Unix Time
print(unixToDatetime)

This question has several problems in it - please limit it to a single issue so it can be applicable to many people. — chris
– chris, Commented Dec 21, 2022 at 17:38
Welcome to SO. Questions should not have multiple questions. Please also give users a way to reproduce the problem. Also, do not assume people know what Unix time is. State clearly what the time format is to make it easy for someone to help — Robert Wilson
– Robert Wilson, Commented Dec 21, 2022 at 19:54
Added example code that works with a single defined data item, but need to adapt it to work on a NetCDF table variable — marky9074
– marky9074, Commented Dec 22, 2022 at 13:33

marky9074 · Accepted Answer · 2022-12-23 15:33:48Z

2

Okay, I worked out how to do it with Pandas:

import netCDF4
import pandas as pd

nc = netCDF4.Dataset('filename.nc')
tvel = nc.groups['vel'].variables['time'][:] # Unix time
dt_tvel = pd.to_datetime(tvel, unit='s') # Datetime

print(dt_tvel)

answered Dec 23, 2022 at 15:33

marky9074

313 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Converting Unix timestamp to datetime NETCDF4

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related