Computing the Canonical Height of a Point in Projective Space

We give an algorithm which requires no integer factorization for computing the canonical height of a point in ${\mathbb{P}}^1(\mathbb{Q})$ relative to a morphism $\phi: $\mathbb{P}${$\mathbb{Q}$}^1 \rightarrow $\mathbb{P}${$\mathbb{Q}$}^1$ofdegree$d \geq 2$.