Write morphometry data for a group into a single MGH or MGZ file.
write.group.morph.standard.sf(filepath, data)
character string, path to the target file, should end with '.mgh' or '.mgz'.
numerical 4d matrix, with first dimension holding 1D data for all vertices of a subject, 2nd and 3rd dimension are of length 1, and 4th dimenions is for each subject.