findCrepuscular: Search for crepuscular light segments

In slisovski/TwGeos: Basic data processing for light-level geolocation archival tags

Search for crepuscular light segments

Description

Search for crepuscular intervals

Usage

findCrepuscular(tagdata, twilights, min.threshold = 0, max.threshold = 60,
  extend.dark = 1, extend.light = 2)

Arguments

tagdata	a dataframe with columns Date and Light that are the sequence of sample times (as POSIXct) and light levels recorded by the tag.
twilights	a dataframe generated by findTwilights.
min.threshold	the light level that defines the dark end of the crepuscular period.
max.threshold	the light level that defines the light end of the crepuscular period.
extend.dark	the number of hours to search towards midnight.
extend.light	the number of hours to search towards noon.

Details

Using the twilights calculated by findTwilights, findCrepuscular searchs for the intervals of reduced light intensity around twilight and returns the dataframe constructed by findTwilights augmented with the start and end times of the crepuscular segment. The sugset of data corresponding to these segments can be extracted with extractCrepuscular.

Value

A dataframe with columns.

Twilight	times of twilight
Rise	logical indicating sunrise
Start	the start of the crepuscular period
End	the end of the crepuscular period

where each row corresponds to a single twilight.

slisovski/TwGeos documentation built on Jan. 27, 2024, 10:43 a.m.