Determine if observation correspond to daylight hours or not
Usage
is_daylight(dt, lat, lon, tz)
Arguments
- dt
A vector of date times either as text or date time objects
- lat, lon
The latitude and longitude of the associated site.
- tz
The HOBOware style GMT offset used to define the "timezone" of the
dates in dt. Probably always "GMT-4:00" but use the value saved to the
metadata file.
Value
A date time object with the dates in dt converted to UTC and with
that timezone correctly set in the object.