  In this paper we describe how the operation of adding a uniton arises via the
DPW method of obtaining harmonic maps into compact Riemannian symmetric spaces
out of certain holomorphic one forms. We exploit this point of view to
investigate which unitons preserve finite type property of harmonic maps. In
particular, we prove that the Gauss bundle of a harmonic map of finite type
into a Grassmannian is also of finite type.
