Row profiles lie in a d-dimensional space. The full set of d principal axes span this space. Suppose fi1, fi2, fi3, ..., fid are the coordinates of row profile i in terms of the principal axes. These coordinates are called the row principal coordinates. The kth principal coordinate for row profile i is fik.
The best k-dimensional subspace is spanned by the first k principal axes. If we project row profile i onto the best k-dimensional subspace, fi1,..., fik are the row principal coordinates of the profile in this subspace.