write.fs.transform.xfm: Write an MNI transform (xfm) file.

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

Write an MNI transform (xfm) file.

Description

Write a transformation in the FreeSurfer xfm format, the format of talairach.xfm files, which store the transformation from the RAS space of a subject to the RAS space of an MNI or Talairach template. Only the first three rows of the matrix are stored, so the transformation must be affine, and it must map RAS coordinates to RAS coordinates.

Usage

write.fs.transform.xfm(tf, filepath, type = "Linear")

Arguments

tf	an fs.transform instance whose matrix maps RAS coordinates to RAS coordinates.
filepath	character string, the full path of the file to write.
type	character string, the value of the Transform_Type entry, 'Linear' by default.

Value

the fs.transform instance tf, invisibly.

See Also

Other header coordinate space: invert.fs.transform(), is.fs.transform(), mghheader.is.ras.valid(), mghheader.ras2vox(), mghheader.ras2vox.tkreg(), mghheader.scanner2tkreg(), mghheader.tkreg2scanner(), mghheader.vox2ras(), mghheader.vox2ras.tkreg(), print.fs.transform(), read.fs.transform(), read.fs.transform.dat(), read.fs.transform.fslmat(), read.fs.transform.itk(), read.fs.transform.lta(), read.fs.transform.xfm(), sm0to1(), sm1to0(), summary.fs.transform(), transform2lps(), transform2ras(), transform2voxel(), transform2world(), write.fs.transform(), write.fs.transform.dat(), write.fs.transform.fslmat(), write.fs.transform.itk(), write.fs.transform.lta()

Examples

xfm_file <- system.file("extdata", "talairach.xfm", package = "freesurferformats", mustWork = TRUE)
tf <- read.fs.transform(xfm_file)
out_file <- tempfile(fileext = ".xfm")
write.fs.transform.xfm(tf, out_file)
max(abs(read.fs.transform(out_file)$matrix - tf$matrix)) # 0
unlink(out_file)

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