Calculate Eye Density by Groups — density

This function calculates the eye density for fixations, grouped by specified variables.

Usage

density_by(
  x,
  groups,
  sigma = 50,
  xbounds = c(0, 1000),
  ybounds = c(0, 1000),
  outdim = c(100, 100),
  duration_weighted = TRUE,
  window = NULL,
  min_fixations = 2,
  keep_vars = NULL,
  fixvar = "fixgroup",
  result_name = "density",
  ...
)

Arguments

x: A data frame containing fixations and additional grouping variables.
groups: A character vector specifying the grouping variables to use.
sigma: A numeric value or a numeric vector specifying the bandwidth(s) for the kernel density estimation. If a vector is provided, multiscale densities are computed. Default is 50.
xbounds: A numeric vector of length 2 specifying the x-axis bounds for the density calculation (default is c(0, 1000)).
ybounds: A numeric vector of length 2 specifying the y-axis bounds for the density calculation (default is c(0, 1000)).
outdim: A numeric vector of length 2 specifying the dimensions of the output density matrix (default is c(100, 100)).
duration_weighted: A logical value indicating whether the density should be weighted by fixation duration (default is TRUE).
window: A numeric vector of length 2 specifying the time window for selecting fixations (default is NULL).
min_fixations: Minimum number of fixations required for computing a density map. Rows with fewer fixations after optional filtering will receive `NULL` in the result column. Default is 2.
keep_vars: A character vector specifying additional variables to keep in the output (default is NULL).
result_name: A character string specifying the name for the density result variable (default is "density").
...: Additional arguments passed to the `eye_density.fixation_group` function.

Value

A data frame containing the original grouping variables, the fixations, and the density result. If `sigma` is a vector, the column specified by `result_name` will contain `eye_density_multiscale` objects.

Examples

# Create a data frame with fixations and a grouping variable
fixations <- data.frame(
  subject = rep(c("A", "B"), each = 25),
  x = runif(50, 0, 1000),
  y = runif(50, 0, 1000),
  duration = runif(50, 1, 5),
  onset = seq(1, 50)
)
eyetab <- eye_table("x", "y", "duration", "onset", groupvar=c("subject"), data=fixations)
#> Error in select_at(., c("x", "y", "duration", "onset", groupvar)): could not find function "select_at"

# Calculate eye density by subject
result <- density_by(eyetab, groups = "subject")
#> Error: object 'eyetab' not found