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Per-trajectory reference direction of a Tracks

Source: R/coords.R
reference.Rd

The reference direction (unit-circle radians) against which each trajectory's relative frame (`rel_theta`/`rel_x`/`rel_y`) is defined. Trajectories with no recorded reference default to `0` (relative frame equals absolute frame).

Usage

reference(x)

# S4 method for class 'Tracks'
reference(x)

Arguments

x

A [`Tracks`].

Value

For `reference()`, a data frame with `id` and `ref_theta` (or `NULL` when none is set).

See also

[set_reference()], [derive_coords()]

Examples

x <- set_reference(cpunctatus[1:3], pi / 2)
reference(x)
#> # A tibble: 3 × 2
#>   id      ref_theta
#>   <chr>       <dbl>
#> 1 10_1_1       1.57
#> 2 10_10_1      1.57
#> 3 10_11_1      1.57