  We show that if a planar graph $G$ has a plane straight-line drawing in which
a subset $S$ of its vertices are collinear, then for any set of points, $X$, in
the plane with $|X|=|S|$, there is a plane straight-line drawing of $G$ in
which the vertices in $S$ are mapped to the points in $X$. This solves an open
problem posed by Ravsky and Verbitsky in 2008. In their terminology, we show
that every collinear set is free.
  This result has applications in graph drawing, including untangling, column
planarity, universal point subsets, and partial simultaneous drawings.
