Remove trajectories entirely, based on velocity thresholds

Remove trajectories from a viewr object that contain instances of velocity known to be spurious.

Usage

exclude_by_velocity(obj_name, vel_min = NULL, vel_max = NULL)

Arguments

obj_name

The input viewr object; a tibble or data.frame with attribute pathviewr_steps that includes "viewr"

vel_min

Default NULL. If a numeric is entered, trajectories that have at least one observation with velocity less than vel_min are removed.

vel_max

Default NULL. If a numeric is entered, trajectories that have at least one observation with velocity greater than vel_max are removed.

Value

A new viewr object that is identical to the input object but now excludes any trajectories that contain observations with velocity less than vel_min (if specified) and/or velocity greater than vel_max

(if specified)

Author

Vikram B. Baliga

Examples

## Import and clean the example Motive data
motive_import_and_clean <-
  import_and_clean_viewr(
    file_name = system.file("extdata", "pathviewr_motive_example_data.csv",
                            package = 'pathviewr'),
    desired_percent = 50,
    max_frame_gap = "autodetect",
    span = 0.95
  )
#> autodetect is an experimental feature -- please report issues.

## See the distribution of velocities
hist(motive_import_and_clean$velocity)


## Let's remove any trajectories that contain
## velocity < 2
motive_vel_filtered <-
  motive_import_and_clean %>%
  exclude_by_velocity(vel_min = 2)

## See how the distribution of velocities has changed
hist(motive_vel_filtered$velocity)