Removes poor quality data based on twilight heuristics
stk_screen_twl(df, threshold = 1.5, dips = 3, step = 100, filter = FALSE)Arguments
- df
skytrackr data frame
- threshold
twilight threshold (default = 1.5)
- dips
allowed number of interruptions during a daylight profile below the twilight threshold before flagging as a poor quality "suspect" day
- step
threshold of the allowed step change in illuminance values between the twilight value and the preceding one. Large jumps and the lack of a smooth transition suggest a false twilight (bird leaving a dark nest site long after or long before dawn or dusk).
- filter
return the data prefiltered, removing all poor quality days or false twilight ones
Value
a skytrackr data frame with poor twilight quality days removed and dusk and dawn timings marked (data is returned as a long format, not a wide format)