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Identify foraging trips in tracking data

opp_get_trips.Rd

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

my_data <- opp_download_data(study = c(1247096889),login = NULL, start_month = NULL,
                            end_month = NULL,season = NULL)
#> Warning: 0 location(s) is/are removed by removeDuplicatedTimestamps

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)
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#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
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#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
#> Warning: CRS object has comment, which is lost in output; in tests, see
#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
#> Warning: CRS object has comment, which is lost in output; in tests, see
#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
#> Warning: CRS object has comment, which is lost in output; in tests, see
#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
#> Warning: CRS object has comment, which is lost in output; in tests, see
#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
#> Warning: CRS object has comment, which is lost in output; in tests, see
#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html
#> Warning: CRS object has comment, which is lost in output; in tests, see
#> https://cran.r-project.org/web/packages/sp/vignettes/CRS_warnings.html



#> Use back arrow in plot pane to browse all plots