Repository navigation
Daylight saving timestamp issue in solarposition.ephemeris #307
Description
In solarposition.ephemeris:
# make output DataFrame
DFOut = pd.DataFrame(index=time)
DFOut['apparent_elevation'] = ApparentSunEl
DFOut['elevation'] = SunEl
DFOut['azimuth'] = SunAz
DFOut['apparent_zenith'] = 90 - ApparentSunEl
DFOut['zenith'] = 90 - SunEl
DFOut['solar_time'] = SolarTime
I get an error when assigning ApparentSunEl to the DFOut column:
ValueError: cannot reindex from a duplicate axis
and I believe the reason comes from the fact that DFOut uses time as index and ApparentSunEl uses time_utc as index; and I think it raises an error because in my case time uses daylight saving and contains duplicate indices. Using ApparentSunEl.values instead should solve the issue.
Activity
wholmgren commentedon Feb 7, 2017
I'm guessing that the same thing happens with
solarposition.pyephem. I don't think it should happen withsolarposition.spa_python. We'll probably need.valueson all of the columns.It would be good to add a test of each method that uses duplicated labels due to DST. You could copy this test
https://github.com/pvlib/pvlib-python/blob/master/pvlib/test/test_solarposition.py#L321-L342
but use a 2 element
timesindex that occurs on the hour before and the hour of DST. You'd also copy the fixtureexpected_solpos_multito createexpected_solpos_dst_transitionor something like that.cwhanse commentedon May 7, 2018
Old issue, but in my opinion requires no change to ephemeris. Times in data should be localized and daylight savings conflicts resolved by the user prior to this function. Maybe this is a requirement for the future pvlib.io.
I recommend closing.
wholmgren commentedon Aug 14, 2018
This might be fixed by #529. I'm going to close for now but please reopen if you continue seeing the issue and plan to make a pull request with a fix.