Outdoor-indoor space: unified modeling and shortest path search

Graph models are widely used for representing the topology of outdoor space (O-Space) and indoor space (I-Space). However, existing models neglect the intersection between O-Space and I-Space, only allowing for computations such as shortest path and nearest neighbor queries in either O-Space or I-Space, separately. In this paper, we present two different outdoor-indoor space (OI-Space) models allowing queries to operate on a mix of both spaces. The first model keeps the distinct nature of the two spaces intact by having explicit connections between outdoor and indoor spaces. The second model abstracts this distinction away, and provides a unified model of outdoor-indoor space. For each model, we present an algorithm that is able to span the two types of spaces to return the real shortest path between two arbitrary points. The experimental evaluations show that the proposed models and algorithms perform well enough to be usable in practice.