A volume axis describes the voxel grid that the volume brain models of a
CIFTI-2 file refer to: its dimensions and the 4x4 transformation matrix that maps the
(0-based) IJK voxel indices to coordinates. The matrix is stored row by row in the
file, and the coordinates it produces are in units of 10^meter_exponent (which is
-3, i.e. millimeters, for the files that Connectome Workbench writes).
Arguments
- dimensions
integer vector of length 3, the dimensions of the voxel grid.
- transformation_matrix
4x4 numeric matrix, the transformation from (0-based) voxel indices to coordinates. There is no default: a CIFTI-2 file does not store the voxel size or the position of a volume anywhere else, so a wrong or invented matrix silently puts the voxels of a structure in the wrong place. Pass the matrix that the template file has (see
cifti.axis.from.template) if you do not know it.- meter_exponent
integer, the exponent of the unit of the coordinates.
Value
a named list with the entries 'dimensions', 'meter_exponent' and
'transformation_matrix', to be passed to cifti.axis.brain.models or
cifti.axis.parcels.
See also
Other cifti functions:
cifti.axis.brain.models(),
cifti.axis.from.template(),
cifti.axis.labels(),
cifti.axis.parcels(),
cifti.axis.parcels.from.annot(),
cifti.axis.scalars(),
cifti.axis.series(),
cifti.brain.model.surface(),
cifti.brain.model.volume(),
cifti.dim.labels(),
cifti.file.type.for.axes(),
cifti.grayordinates(),
cifti.header.from.axes(),
cifti.label.table(),
cifti.parcel(),
cifti.parcels(),
cifti.series.info(),
cifti.structure.data(),
cifti.structures(),
print.fs.cifti(),
print.fs.cifti.data(),
print.fs.connectome(),
read.cifti(),
read.cifti.header(),
read.cifti.rows(),
read.fs.connectome.cifti(),
write.cifti(),
write.fs.connectome.cifti(),
write.fs.morph.cifti(),
write.fs.parcellated.cifti(),
write.fs.parcellation.cifti(),
write.fs.series.cifti()