  We study the localization number of incidence graphs of designs. In the
localization game played on a graph, the cops attempt to determine the location
of an invisible robber via distance probes. The localization number of a graph
$G$, written $\zeta(G)$, is the minimum number of cops needed to ensure the
robber's capture. We present bounds on the localization number of incidence
graphs of balanced incomplete block designs. Exact values of the localization
number are given for the incidence graphs of projective and affine planes.
Bounds are given for Steiner systems and for transversal designs.

Combinatorics;Discrete Mathematics