read.trk.records: Read the track records of a TRK file.

In freesurferformats: Read and Write 'FreeSurfer' Neuroimaging File Formats

Read the track records of a TRK file.

Description

Reads track records from the current position of the connection until the end of the file or until max_tracks records have been selected. Coordinates and per-point scalars are stored interleaved in the file, so each record is read with a single readBin call and split afterwards, instead of reading one point at a time.

Usage

read.trk.records(
  fh,
  endian,
  n_scalars,
  n_properties,
  max_tracks = Inf,
  expected_tracks = NA_real_,
  skip_tracks = 0L,
  bbox = NULL,
  transform = NULL,
  gzipped = FALSE,
  filepath = ""
)

Arguments

fh	a connection opened in binary read mode, positioned at the start of the first track record.
endian	character string, 'little' or 'big'.
n_scalars	integer, number of scalars per point.
n_properties	integer, number of properties per track.
max_tracks	numeric, maximum number of tracks to select. Use Inf to read until the end of the file.
expected_tracks	numeric, the number of tracks stated in the header, or NA if the header does not contain a usable count. Used to report truncated files, never to limit reading.
skip_tracks	integer, the number of tracks to skip before selecting any, see read.dti.trk.
bbox	numeric vector of length 6 or NULL, a bounding box, see read.dti.trk.
transform	4x4 numeric matrix or NULL. If given, it is applied to the coordinates of every track as it is read, before the bounding box filter is evaluated and before they are stored. This is used to filter in the target coordinate system without transforming the whole result twice.
gzipped	logical, whether the connection reads a gzip-compressed file, see is.gzip.file. R cannot seek in such a connection, so skipped tracks are skipped by reading and discarding them.
filepath	character string, the path of the file, used in error messages and for skipping in compressed files.

Value

named list with entries coords (matrix with 3 columns and one row per point), lengths (integer vector, points per track), scalars (matrix or NULL) and properties (matrix or NULL).

freesurferformats documentation built on Sept. 25, 2026, 1:07 a.m.