Establishing Indoor Subspacing Requirements of an Lod (Level of Detail) Model for Generating Network-Based Topological Data

Abstract

Abstract. Nowadays, the complexity of structures in urban environments and the interest in location-based applications increase simultaneously. Along with this is the rise in demand for the firm establishment of data models representing these spaces. Establishing network models that portray topological relationships of space have strengthened support for navigation applications. However, researchers have revisited the limitations of existing standards. As analogous standards have specifications for expressing space at various scales, most have focused on outdoor space or the geometric aspect. Hence, this paper proposes subspacing requirements for a Level of Detail (LOD) model for network-based topological data. We examine various constraints that influence space partition and align these with various application cases for indoor navigation. Through these, we investigate appropriate space subdivision approaches for each level according to applicable constraints and recommended applications. This study poses as an initial study towards establishing a general framework for implementing a 3D hierarchical network-based topological data model.

An Indoor Space Subspacing Framework for Implementing a 3D Hierarchical Network-Based Topological Data Model

“…In most studies of indoor space, such as the subspacing approaches presented in [6,22,53,54], the rooms are considered the smallest cells or units. However, based on the subspacing framework presented in [55], and the subdivision approaches presented in [5,56], there are smaller elements of space within rooms. Considering a room's different areas, such as that shown in Figure 3, allows for the room's division into smaller units to obtain a much more granular subspace.…”

“…Therefore, one must generate NRS data representing the said relationships through a network structure because it is more appropriate for navigation and portrayal of constraints in indoor space. Figure 5 illustrates the levels of hierarchy representing indoor space at increasing spatial scales, modified from the LOD specification from [55] and adapted to the space hierarchy discussed in the previous section. The levels of detail begin at the fundamental element of spatial hierarchy, specifically an entire un-subspaced building at Level 0.…”

“…At Level 4, we consider the navigation network characterized by actual free spaces inside the rooms. Notably, together with the recommended constraints and space subdivision methods, Claridades et al ( 2021) also suggested corresponding application use cases for each level [55].…”

“…Based on the class diagram in Figure 10, each of the nodes in Figure 12 represents an instance of the 1 class, which is associated with the Building class. Figure 12 shows the result for the Level 1 network, which is applicable to floor-to-floor navigation activities, such as when entire floor levels are target destinations [55]. Accordingly, the structure of the building in this use case was composed of three major wings.…”