opp_get_trips: Identify foraging trips in tracking data

In popovs/OPPtools: This package contains tools and templates to analyze seabird tracking data

Identify foraging trips in tracking data

Description

Uses criteria related to distance from colony, trip duration, and size of gaps in tracking data to identify and classify trips from a nest or colony. It is a wrapper for track2KBA::tripSplit that applies custom criteria for classifying trips.

Usage

opp_get_trips(
  data,
  innerBuff,
  returnBuff,
  duration,
  gapTime = 1,
  gapDist = 5,
  gapLimit = 100,
  showPlots = TRUE,
  plotsPerPage = 4
)

Arguments

data	Tracking data formated using track2KBA or opp2KBA
innerBuff	Minimum distance (km) from the colony to be in a trip. 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'. Defaults to 20.
duration	Minimum trip duration (hrs)
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.
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.
showPlots	Logical (T/F), should plots showing trip classification by generated?
plotsPerPage	Numeric indicating the number of individuals to include in a single plot. Defaults to 4.

Details

This returns a SpatialPointDataFrame in a longlat projection. Most fields in the dataframe come from the output of track2KBA::tripSplit. This function also adds fields for:

• DiffTime - Difference in hours between locations

• DiffDist - Difference in distance between locations

• Type - Type of trip: Non-trip, Complete, Incomplete, or Gappy

• TripSection - An integer index noting sections of a the trip that are separated by gaps

Gaps in trips are defined as any pair of locations that are farther apart in time than gapTime and farther apart in space than gapDist.

Examples

## Not run: 
my_data <- opp_download_data(study = c(1247096889),login = NULL, start_month = NULL,
                            end_month = NULL,season = NULL)

my_track2kba <- opp2KBA(data = my_data)

my_trips <- opp_get_trips(data = my_track2kba, innerBuff  = 5, returnBuff = 20,
                         duration  = 2, gapLimit = 100, gapTime = 2, gapDist = 5,
                         showPlots = TRUE)

## End(Not run)

popovs/OPPtools documentation built on July 8, 2023, 2:29 a.m.