  We develop an algorithm that determines, for a given squarefree binary form
$F$ with real coefficients, a smallest representative of its orbit under
$\operatorname{SL}(2,\mathbb Z)$, either with respect to the Euclidean norm or
with respect to the maximum norm of the coefficient vector. This is based on
earlier work of Cremona and Stoll. We then generalize our approach so that it
also applies to the problem of finding an integral representative of smallest
height in the $\operatorname{PGL}(2,\mathbb Q)$ conjugacy class of an
endomorphism of the projective line. Having a small model of such an
endomorphism is useful for various computations.
