  We explore the distance-redshift relation using a cosmographic methodology,
and show how the cosmographic parameters can be used to determine the redshift
of transition from deceleration to acceleration. Such a transition at a low
redshift occupies only a small region of the available parameter space, and the
prior assumption of an early period of deceleration can significantly change
the posterior constraints. We use available type Ia Supernovae (SN-Ia) and
Baryon Acoustic Oscillation (BAO) data sets to determine the cosmographic
deceleration $q_0$, jerk $j_0$, snap $s_0$ and lerk $l_0$ parameters. The
parameters are consistent with the $\Lambda$CDM model for a flat universe
within 2-sigma. We derive constraints on the redshift of transition from
deceleration to acceleration for the different expansions, and find $z_{\rm
acc} > 0.14$ at 95% confidence in the most conservative case.
