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Validate an anipoint

Source: R/anipoint_validate.R
validate_anipoint.Rd

Re-checks, on demand, that an anipoint's metadata still describes the frame it is attached to. The two drift apart silently under ordinary dplyr work: dplyr::select() drops a column without touching the metadata that names it, and assignment can change a column's type. The invariants are therefore checked rather than assumed:

Usage

validate_anipoint(data, rate_tolerance = 0.01)

Arguments

data

An anipoint object.

rate_tolerance

How far the declared sampling_rate may be from the rate the index is spaced at before it warns, relative to the declared rate. The default, 0.01, lets real timestamps through: a camera log that averages 30.11 Hz agrees with a declared 30 Hz. Lower it for a strict check, such as 1e-6 for an index computed from the rate.

Value

The input data, invisibly.

Details

  • the index column is present and numeric — hard error;

  • every declared column is present in the data — hard error;

  • every position column is numeric — hard error;

  • coordinate_system agrees with the axis roles — warning only. The frame is still usable, and the field is derived rather than declared, so it can be refreshed;

  • identity, temporal context and the index together name one observation per row — warning only (#49);

  • a declared sampling_rate agrees with the spacing of the index, to within rate_tolerance — warning only (#114). The spacing is the median gap, so a few dropped frames do not count against it.

See also

ensure_is_spatial() for the spatial subset of these checks, which is the part downstream filters need on every call; validate_anievent() for the anievent equivalent.

Examples

af <- anipoint(time = 1:5, x = 1:5, y = 1:5)
validate_anipoint(af)