Over the past few years Personal Navigation Systems have become an established tool for route planning,but they are mainly designed for outdoor environments.Indoor navigation is still a challenging research area for several reasons: positioning is not very accurate,users can freely move between the interior boundaries of buildings,path network construction process may not be easy and straightforward due to complexity of indoor space configurations.Therefore the creation of a good network is essential for deriving overall connectivity of a building and for representing position of objects within the environment.This paper reviews current approaches to automatic derivation of route graphs for indoor navigation and discusses some of their limitations.Then,it introduces a novel algorithmic strategy for extracting a 3D connectivity graph for indoor navigation based on 2D floor plans.