Polar generalised additive model (polar GAM)

It fits a generalised additive model (GAM) to transformed polar tongue data and it returns a model in polar coordinates. Use plot_polar_smooths() for plotting.

polar_gam(
  formula,
  data,
  origin = NULL,
  fan_lines = c(10, 25),
  AR_start = NULL,
  ...
)

Arguments

formula: A GAM formula.
data: A data set containing the spline coordinates (cartesian coordinates must be in columns named X and Y, polar coordinates in columns named angle and radius; these are the defaults in data imported with read_aaa()).
origin: The coordinates of the origin as a vector of c(x, y) coordinates.
fan_lines: A numeric vector with two fan lines (the default is c(10, 25)).
AR_start: The AR.start argument to be passed to mgcv::bam().
...: Arguments to be passed to mgcv::bam().

Value

An object of class "gam" as described in

gamObject.

Details

It is advised to fit a separate model per speaker, unless you have a working method for inter-speaker normalisation of the coordinates.

Examples

# \donttest{
library(dplyr)
tongue_it01 <- filter(tongue, speaker == "it01")
pgam <- polar_gam(Y ~ s(X, by = c2_place) + s(X, word, bs = "fs"),
data = tongue_it01)
#> The origin is x = 14.3901267816422, y = -65.2315420525847.
# }