Convert a data frame to anipoint

Usage

as_anipoint(
  data,
  metadata = list(),
  variables_what = NULL,
  variables_when = NULL,
  variables_where = NULL,
  index = NULL,
  root = NULL
)

Arguments

data: A data frame with movement data.
metadata: A list of metadata to attach to the anipoint.
variables_what: Character vector of identity columns that together define a unique entity, and which the frame is grouped by. If NULL (the default), detected from the data: whichever of model, individual, subject, track and keypoint are present, in the order list_recognised_variables_what() lists them. Order carries no meaning of its own — see its documentation. An anipoint needs at least one identity variable, so if none of them is found, a keypoint column is added with the value "centroid". Pass character(0) to declare no identity variables at all — a deliberate opt-out, which leaves the frame ungrouped. Every column named here must exist in data.
variables_when: Character vector of temporal columns that together define a unique timepoint. If NULL (the default), detected from the data: whichever of observation, session, trial and time are present, minus the index. These are the temporal context — which session, which trial — and, together with variables_what, they are what the frame is grouped by. The index itself is declared separately and is never one of them.
variables_where: The spatial columns that together define position. Either a plain character vector of column names, in which case the name is taken to be the axis role, or a vector named by axis role — c(x = "u", y = "v") — which lets the columns be called anything. The roles themselves are a closed set (x, y, z, rho, phi, theta), so that transformations between coordinate systems stay well defined; an unrecognised role is rejected by name. If NULL (the default), detected from the data.
index: Length-one character vector naming the column the frame is indexed by — the position of each row within its temporal context. It is never a grouping variable. If NULL (the default), the frame's existing declaration is kept, or "time" for a frame that has none. The column must exist and be numeric; it may be called anything.
root: For an as_anisegment() frame: an anipoint holding the root point's trajectory, such as the frame the segments came from. The other points are rebuilt by walking the structure's segments outward from it, so edits to the segments (such as constant lengths) carry into the positions.

Value

An anipoint object

Examples

df <- data.frame(
  time = 1:3, individual = 'a', keypoint = 'centroid',
  x = c(0, 1, 2), y = c(0, 1, 0)
)
as_anipoint(df)
#> # Individuals: a
#> # Keypoints:   centroid
#>   individual keypoint  time     x     y
#>   <fct>      <fct>    <int> <dbl> <dbl>
#> 1 a          centroid     1     0     0
#> 2 a          centroid     2     1     1
#> 3 a          centroid     3     2     0