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Explore how different values of minDist influence total number of trips

opp_find_minDist.Rd

Calculates the number of trips that go farther than returnBuff for a range of minimum distance values that a bird must travel from the colony to be considered in a trip. This is useful for ensuring that the minimum trip distance separates all long trips.

Usage

opp_find_minDist(
  data,
  minDist_range = 1:10,
  returnBuff = 20,
  duration = 1,
  gapLimit = 100,
  gapTime = 1,
  gapDist = 10
)

Arguments

data

Polygon output from track2KBA::findSite()

minDist_range

Vector of ditances (km) from the colony to calculate how minimum distance influences total number of long foraging trips. Used to label trips as 'Non-trip'. Defaults to 5

returnBuff

Outer distance (km) to capture trips that start and end away from the colony. Used to label trips as 'Incomplete' and for assessing the effect of minDist on total number of trips. Defaults to 20.

duration

Minimum trip duration (hrs)

gapLimit

Maximum time between points to be considered too large to be a contiguous tracking event. Can be used to ensure that deployments on the same animal in different years do not get combined into extra long trips. Defaults to 100 days.

gapTime

Time (hrs) between successive locations at which trips will be flagged as 'Gappy'. Used in connection with gapDist, such that locations must be farther apart in both time and space to be considered a gap.

gapDist

Distance (km) between successive locations at which trips will be flagged as 'Gappy'. Used in connection with gapTime, such that locations must be farther apart in both time and space to be considered a gap.

Details

With lower sampling frequency or if GPS fixes are not taken at or near the colony, multiple foraging trips may be combined if minDist is too small. Look for the minDist value where the number of trips begins to asymptote. Selected values should be confirmed by calling opp_get_trips directly with showPlots = TRUE.