Minimizing the Oriented Diameter of a Planar Graph

We consider the problem of minimizing the diameter of an orientation of a planar graph. A result of Chvلtal and Thomassen shows that for general graphs, it is NP-complete to decide whether a graph can be oriented so that its diameter is at most two. In contrast to this, for each constant l, we describe an algorithm that decides if a planar graph G has an orientation with diameter at most l and runs in time O ( c | V | ) , where c depends on l.