Distance constrained network location involves locating m new facilities on a transport network G so as to satisfy upper bounds on distances between pairs of new facilities and pairs of new and existing facilities. The problem is 𝒩𝒫-complete in general, but polynomially solvable for certain classes. While it is possible to give a consistency characterization for these classes, it does not seem possible to give a global description of the feasible set. However, substantial geometrical insights can be obtained on the feasible set by studying its projections into the network. The j-th projection defines the j-th composite region which is the set of all points in G at which new facility j can be feasibly placed without violating consistency. The authors give efficient methods to construct these regions for solvable classes without having to know the feasible set and discuss implications on consistency characterization, what if analysis, and recursive solution constructions.
