write.dti.tck: Write tracks to a file in MRtrix TCK format.

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

Write tracks to a file in MRtrix TCK format.

Description

Writes streamlines in the TCK format described at https://mrtrix.readthedocs.io/en/latest/getting_started/image_data.html. The format stores a triplet of NaN values between streamlines and a triplet of Inf values at the end. The output is read by MRtrix and by read.dti.tck.

Usage

write.dti.tck(
  tracts,
  filepath,
  datatype = "Float32LE",
  gzip = NULL,
  header = list()
)

Arguments

tracts	the tracks to write, either an fs.tracts instance or a list of numeric matrices with 3 columns, see write.dti.trk.
filepath	character string, the path of the file to write.
datatype	character string, one of 'Float32LE' (the default, and what MRtrix writes), 'Float32BE', 'Float64LE' or 'Float64BE'.
gzip	logical or NULL, whether to gzip-compress the output. If NULL (the default), the file is compressed when the file name ends in '.gz'.
header	named list of additional header entries to store in the file, e.g., the header of the file the tracks were read from. The entries 'id', 'datatype', 'count', 'file' and 'derived' are always computed by the readers and cannot be set.

Value

the file path, invisibly.

Note

Tracts without any point cannot be represented in the TCK format: they are written as a bare delimiter, which every reader (including this package and 'nibabel') drops again, so the file reads back with fewer tracts than it was written from. Writing such a file raises a warning. write.dti.trk preserves empty tracts.

Examples

## Not run: 
tck <- read.dti.tck("brain.tck", max_tracks = 1000);
write.dti.tck(tck$tracks, "first_1000.tck", header = tck$header);

# Round trip through a compressed file:
write.dti.tck(tck$tracks, "copy.tck.gz");

## End(Not run)

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