OverflowError: date value out of range in num2date

[lyashevska]

Hi,

I am trying to convert this object using num2date. However I get OverflowError: date value out of range
What could possibly cause this behaviour and how it can be fixed. Thanks.

<type 'netCDF4._netCDF4.Variable'>
float64 time(time)
units: days since 1800-01-01 00:00:0.0
long_name: Time
actual_range: [-657073. -656739.]
delta_t: 0000-01-00 00:00:00
avg_period: 0030-00-00 00:00:00
prev_avg_period: 0000-00-07 00:00:00
ltm_range: [ 58804. 69730.]
standard_name: time
axis: T
unlimited dimensions: time
current shape = (12,)
filling off

times = f.variables['time']

times[:]
array([-657073., -657042., -657014., -656983., -656953., -656922.,
-656892., -656861., -656830., -656800., -656769., -656739.])

times.units
u'days since 1800-01-01 00:00:0.0'

netCDF4.version
'1.2.7'

[jswhit]

num2date can't handle dates before 0001-01-01. The first element in your times array (-657073) is before that date using the standard (mixed Julian/Gregorian) calendar. It works if you used 'calendar = Julian' since the first date is 1-01-12 00:00:00. What calendar did you intend to use?

[jswhit]

Stand by - I think this may actually be a bug in how negative times are treated (I don't think the correct date is before 0001-01-01).

[jswhit]

fix in pull request #660

Can you confirm that the correct date for -657073 is 0001-01-01?

[jswhit]

Just checked using https://erddap.marine.ie/erddap/convert/time.html?n=-657073&units=days+since+1800-01-01T00%3A00%3A00Z and this is correct. I'll merge this tomorrow if there are no comments.

[lyashevska]

Thank you for your prompt response. Please go ahead with the merge. I do not have any comments.

[PearlW1]

if your start_date is '2019-09-08' and end_date is '2019-09-01' ,then use those date in computition, the error "OverflowError: date value out of range in num2date " will be appeared.
how to solve this question?
let start_date is '2019-09-01' and end_date is '2019-09-08', this setting will work.