sph2fs: Transform spherical coordinates to FreeSurfer surface space...

In fsbrain: Managing and Visualizing Brain Surface Data

Transform spherical coordinates to FreeSurfer surface space to plot things around a brain.

Description

Transform spherical coordinates to FreeSurfer surface space to plot things around a brain.

Usage

sph2fs(
  lon,
  lat,
  radius = surf.radius.fsaverage(),
  center = surf.center.fsaverage(),
  deg = TRUE
)

Arguments

lon	numerical vector, the longitudes. See 'deg' for unit information.
lat	numerical vector, the latitudes. See 'deg' for unit information.
radius	numerical vector, the radii. Defaults to the radius of the combined mesh from the fsaverage lh and rh surfaces.
center	numerical vector of length 3, the x, y, and z coordinates of the target center. The spherical coordinates are transformed on the unit sphere, and this parameter is used to translate the resulting cartesian coordinates to a new center, typically the center of the surface meshes or MRI volume or substructures. If you want no translation, pass c(0,0,0).
deg	logical, whether to use degrees (as opposed to radians) as the unit for 'lat' and 'lon'.

Note

This function can be used to plot things in FreeSurfer space using spherical coordinates, as commonly used in EEG to define electrode positions.

Examples

## Not run: 
    # Draw voxels on a sphere around fsaverage:
    lat = seq.int(from=0, to=360, by=30);
    lon = rep(0, length(lat));
    vis.fs.surface('~/software/freesurfer/subjects/fsaverage/surf/lh.white');
    fsbrain::rglvoxels(sph2fs(lat, lon), voxelcol = 'red');
    fsbrain::rglvoxels(sph2fs(lon, lat), voxelcol = 'green');

## End(Not run)

fsbrain documentation built on Sept. 27, 2026, 1:07 a.m.