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Add motion variables to data

Source: R/data.R
add_motion_variables.Rd

This function adds several motion variables to an already existing dataset. These motion variables are then used by predped to compute utilities, allowing for estimations in the long run. The variables that are added are speed, orientation, and the cell to which a person moved (as defined by the M4MA).

Usage

add_motion_variables(
  data,
  velocities = c(1.5, 1, 0.5),
  orientations = c(72.5, 50, 32.5, 20, 10, 0, -72.5, -50, -32.5, -20, -10),
  time_step = 0.5,
  threshold = qlnorm(0.25, -2.95, 0.64)/time_step,
  initial_conditions = FALSE
)

Arguments

data

Instance of a data.frame containing the data you want to transform.

velocities

Numeric vector denoting the changes in speeds as assumed by the M4MA. Defaults to 1.5 (acceleration), 1, and 0.5 (deceleration).

orientations

Numeric vector denoting the changes in orientation as assumed by the M4MA. Defaults to 72.5, 50, 32.5, 20, 10, 0, 350, 340, 327.5, 310, 287.5 (note that the larger angles are actually the negative symmetric versions of the smaller angles).

time_step

Numeric denoting the time between each iteration. Defaults to 0.5 (the same as in simulate).

threshold

Numeric denoting under which observed value for speed the cell to which an agent has moved should be put to `0`. Defaults to a value based on the observed measurement error in our system.

initial_conditions

Logical denoting whether the added columns should include the initial conditions (that is, speed, orientation, and position at the previous time point) alongside their current alternatives. Useful when one wants to compute the values of the utility-related variables from the data. Defaults to FALSE.

Details

The provided dataset should at least have the following columns: - x, y: Coordinates at which a person was standing at a given time - time: A continuous variable that denotes the time at which the measurement took place. - id: The identifier given to the person whose position was measured. - goal_id: The identifier given to the goal the person had to move towards while their position was being measured. - goal_x, goal_y: The position of the goal the person had to move to while their position was being measured.

Examples

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