This function add timeUTC as POSIX class, local time and ending sampling time
Usage
obs_agg(
dt,
cols = c("year", "month", "day", "hour", "minute", "second", "time", "time_decimal",
"value", "latitude", "longitude", "altitude", "pressure", "u", "v", "temperature",
"type_altitude"),
by = c("key_time", "site_code", "altitude_final", "type_altitude", "lab_1_abbr",
"dataset_calibration_scale"),
fn = "mean",
verbose = TRUE
)