Process bouts and GPS epochs into walk bouts

This function processes bouts and GPS epochs into walk bouts. It uses a set of parameters and constants to determine whether an epoch is active or inactive, the minimum number of epochs for a period of activity to be considered as a potential bout, the local time zone of the data, and other relevant information. It takes in two data frames, "bouts" and "gps_epochs", and returns a processed data frame, "walk_bouts", with added columns "bout", "bout_radius", "bout_category", "complete_days", "non_wearing", and "speed".#'

Usage

process_bouts_and_gps_epochs_into_walkbouts(
  bouts,
  gps_epochs,
  ...,
  collated_arguments = NULL
)

Arguments

bouts

a data frame containing bout information

gps_epochs

a data frame containing GPS information

...

additional arguments to be passed on to other functions

collated_arguments

a list of arguments collated from other functions

Value

a processed data frame, "walk_bouts", with added columns "bout", "bout_radius", "bout_category", "complete_days", "non_wearing", and "speed"#'

Details

The function first collates the arguments passed to it with the collate_arguments() function. It then merges "gps_epochs" and "bouts" data frames by "time" column, and orders the resulting data frame by "time". Then, it generates the "bout_radius" using the generate_bout_radius() function, which calculates the radius of a bounding circle that would be considered a dwell bout. Next, the function evaluates the completeness of GPS data using the evaluate_gps_completeness() function, which determines the number of GPS observations within a bout and the ratio of data points with versus without GPS data. Finally, the function generates the "bout_category" using the generate_bout_category() function, which determines whether a bout is a walk bout or a dwell bout, and calculates the complete days, non-wearing periods, and speed. The function categorizes bouts into the following categories:

• dwell bout

• non-walk too vigorous

• non-walk too slow

• non-walk too fast

• unknown lack of gps

NOTE: If there are multiple GPS points associated with a given epoch interval, we use the latest possible GPS data point within that epoch. As such, median walking speed is calculated for only the latest available GPS data point in each epoch.

NOTE: The median speed is calculated using only the GPS data points that remain after GPS data processing. All GPS data points that are outliered for the calculation of a bout radius, are, however, included in the assessment of GPS completeness as they are outliers but are still present GPS data points.

NOTE: Outliered data points are excluded from the radius calculation but are included in subsequent functions that assess GPS completeness. They are also returned from these functions with the original data and all new variables.