Comparing different TMY/EPW providers : inconsistency of data?

ladybug-tools
18

Hi @josephyang,

For me in the original epw file (in accordance with the definition here) :

12:00 datetime in the hourly data collection represents the accumulated radiation in between 11:00 and 12:00.

But because internally in LDBT there is a shift of the time stamps of one hour ahead of time (24:00 the 31/12 is pushed to 00:00 the 01/01) to conform to DateTime standard (where 24:00 does not exist as time goes from 00:00:00 to 23:59:59), now in LDBGT :

12:00 datetime in the hourly data collection represents the accumulated radiation in between 12:00 and 13:00.

So because of this shift :

  • A “point in time” data (like temperature, wind speed, wind direction, …) is still represented by the same timestamp (but 24:00 of day N is now 00:00 of day N+1)
  • An “accumulated” data (like radiation) over an hour is now represented by the timestamp opening the period (while it was represented by the timestamp closing this period in the epw file).

This Is what my figure was trying to illustrate and I think this is in accordance to what is explained in the docstring of the EPW.py module.

Does it make sens to you ?

Hopefully @chris can confirm (or not) if may explanation is correct.

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