Theories and Models of Indoor Space

Although people’s daily lives are situated in both outdoor and indoor space, they actually spend most of their time in indoor environments. However, traditional geospatial science focuses mainly on outdoor space. Also, when we consider informatic assistance for the task of navigation, GPS has been indispensable for assisting navigation in outdoors. Up to now, navigation assistance for indoor space is much less well developed. But applications need to consider both outdoor and indoor spaces. Therefore, research on providing theories and models of indoor space is necessary. This dissertation provides the development of theories and models representing the structure of indoor space and supporting navigation within it. A fundamental technique used is ontology development, which is the computerized specification of the meaning of terms used in specific domains. After investigating the similarities and differences between outdoor and indoor spaces in the context of navigation, the ontology of indoor space that can be integrated with outdoor space is developed. Four levels of ontologies are constructed based on the idea of modularization: upper ontology (the most general concepts), domain ontologies (concerned with the specific structure of the spaces), navigation task ontology, and application ontologies (specific user types and applications). We also work on making extensions to existing formal spatial models and developing related computational algorithms. A pure topological structure combinatorial map is extended to consider geometric information. A new formal concept dual map is proposed in order to make a correct dual connection between the structure of an indoor space and its navigation construct. Using the theories and algorithms developed in this research, we develop an approach to automatic construction of navigation graphs (underlying data structures that systems use to support human wayfinding) from building plans. The approach integrates topology, geometry, and semantics. To demonstrate and evaluate the proposed navigation graph generation approach, a case study was developed using OpenStreetMap (OSM) based on Boardman Hall and its surroundings, which serves as a test-bed for the developed constructions and algorithms. A simple human subject experiment was also conducted to partially evaluate the case study. Ontologies are also evaluated by the developed case study. The results of the case study and human experiment showed that the generated navigation graph provides a collection of appropriately positioned navigation nodes, as well as appropriate connecting navigation edges