1、LI Yuan; HE Zizhang - 3D Indoor Navigation, 44th ISOCARP Congress 2008 1 3D Indoor Navigation: a Framework of Combining BIM with 3D GIS 1 Introduction Navigation, also called as finding ones way, whether in real or electronic worlds, is a complex human activity (Burnett, Smith Zhu, Li as a result, t
2、he effects of 3D indoor navigation are actually far from expectation. LI Yuan; HE Zizhang - 3D Indoor Navigation, 44th ISOCARP Congress 2008 2 Successful 3D indoor navigation depends on: accurate and updated geometry and semantics of building; correct indoor positioning; flexible navigation routes c
3、onsidering human characteristics; information about threats and building accessibility, etc. The developments in the building-design field have resulted with the emergency of an industry standard Building Information Model (BIM), being capable of restoring both geometric and semantic information. 3D
4、 Geographic Information System (3D GIS), known as an ideal tool for representing 3D geometry, semantic as well as topology, has been gradually utilized in many disciplines. Recent studies demonstrated that it is possible to transfer 3D geometric and semantic information from BIM into a 3D GIS enviro
5、nment(Isikdag 2006). The next step, proposed in this paper, is to extend the research and to explore a framework of 3D GIS-based, BIM information-supported, topologic analysis-oriented indoor navigation. The remainder of this paper is organized as follows. Section 2 introduces the functional require
6、ment for 3D indoor navigation. Section 3 discusses the information from Building Information Model (BIM). Section 4 covers the topological elements involved in navigation. Section 5 analyzes the prototype and implementation issues. Finally, concluding remarks are presented in Section 6. 2 Functional
7、 requirements for 3D indoor navigation The basic routing and navigation capabilities on a roadmap are extremely fundamental for any time-critical applications (TCA), such as location-based service (LBS), intelligent transportation system (ITS) and emergency response (ER). The general functional requ
8、irements for navigation are multidimensional, covering three levels. Level 1 is space level, including microscopic sub-level, mesoscopic sub-level and macroscopic sub-level. Level 2 is information level, containing six sub-levels, namely temporal information, spatial information, content information
9、, data type information, data format information and navigation control information. Level 3 is service level, requiring four sub-levels, namely accuracy, rapidness, adaptability and convenience. Level 1: Space Level circle6 For microscopic sub-level, the research space is focused on 3D, for example
10、, 3D indoor or 3D lane-based navigation. circle6 For mesoscopic sub-level, the space is 2.5D, where the research considers the generalized traffic volume in different directions of each street or multi-model navigation among road network, sub-way network, etc. circle6 For macroscopic sub-level, only
11、 road space and non-road space have been classified, the research aims at the street level. The traditional digital urban map was mainly represented at this level. Level 2: Information Level circle6 For temporal information, it includes historical, online and predicted information. LI Yuan; HE Zizha
12、ng - 3D Indoor Navigation, 44th ISOCARP Congress 2008 3 circle6 For spatial information, the inputting information may be o-dimensional, 1-dimensionl, 2-dimensional and 3-dimensional, which represents point, linear, area and volume object individually. circle6 Content information means what kinds of
13、 objects or events are to be considered into routing and navigation. The content information may include road network structure, the vehicle/pedestrian location, event location, disaster location, etc. circle6 Data type information refers to words, pictures, models, voices, figures, etc. circle6 Dat
14、a format information may come from DXF, SHP, 3DS, E00, GML, etc. circle6 Navigation control information consists of the restriction rules at turns, speed limits at corridor, types of passing (uni- or bi-directional), etc. Level 3: Service Level circle6 Accuracy means the route is provided in a right
15、 way and is reliable. Since the in-built environment is very complicated, especially in emergency situation when lots of events can be occurred, a rational routing algorithm should be adopted in order to deal with the uncertainty and dynamic factors. circle6 Rapidness refers to the quick calculation
16、 of route and the quick representation for the route. Because of navigation is a kind of time-critical application, the task should be guaranteed by sound network calculation methods and suitable data dispatching strategies. circle6 Adaptability means that the navigation behavior should satisfy diff
17、erent kinds of users, for example, the evacuated people, the rescue staff, the emergency manager. circle6 Convenience means the various output modes, for example, voice, 3D graph, image schema, etc. 3D indoor navigation belongs to microscopic sub-level. The information to support 3D indoor navigatio
18、n discussed in this paper mainly come from BIM model, which covers both 3D geometry and semantics with temporal constraints. The contents of the information to support 3D indoor navigation should include the plan map of each floor, semantic description of each building component, positional reports
19、of pedestrian, exits position of the building, etc. Navigation control information for 3D indoor navigation should include the topologic element for network analysis and geometric elements for route presentation. Basically, topologic elements defines the nodes and links, which represent the room spa
20、ce and corridor space (or granting polygon such as doors, exits or windows) respectively. Geometric elements define the visualization components, and these components can be photorealistic or symbolic. Because of the huge data volume in the 3D GIS environment, it is impossible to load all the compon
21、ents simultaneous. Besides, the navigation environment is user-focused, that is to say, only the building components that around the user should be visualized. 3D indoor navigation requires accurate evacuation route by considering all kinds of evacuation situation, such as reason for moving. Take ea
22、rthquake as example, the elevator cannot be taken into consideration for the vertically travelable link; in fire disaster, if a door has been blocked, a window can be takes as a travelable link to corridor. Accuracy also connects to the mode of movement and even time of day. The age, the health cond
23、ition of the user will affect the choosing of a route. For a shopping mall, some section will be temporally closed and in such situation, the route is also different with usual. Rapidness is also important for indoor LI Yuan; HE Zizhang - 3D Indoor Navigation, 44th ISOCARP Congress 2008 4 navigation
24、 because it is tightly linked with time-critical application. Adaptability for 3D indoor navigation has some special meaning. First, different people have different ways for knowing the indoor environment. For the staffs who work in the building, the main guiding marks (such as emergency exits, stai
25、r, corridor, and hall) are sufficient for evacuation. But for tourist, they have no experience for the inner structure; they dont know the exact place of emergency exits and the distance from them. In such condition, more detailed landmark should be given in order to enhance their understanding for
26、the environment. Second, different time calls for different ways of navigation. In night time lots of building component cannot be seen in the dark, however special objects are illuminated at night. Therefore, the illuminated objects are far more important than the landmark in daytime for 3D indoor
27、navigation at night. Convenience for 3D indoor navigation needs all kinds of presentation modes for navigation information, including voice, graph, 3D model, etc. Because most of the 3D indoor navigation application is user-focused, at the same time the mobile technique has been mature enough to sup
28、port the instant transmission for 3D scenario, therefore it is possible to provide visual map to single user via mobile, also called as mobile navigation. In this paper, the main focus is on 3D navigation map instead of voice navigation. The traditional indoor navigation has two main characteristics
29、: 1) the main task is to find the nearest POI (from the user lactation to destination); 2) it is based on geometric location modeling. Such navigation architecture is not intelligent because it omits the consideration of user profiles and the rich semantic information within buildings. The architect
30、ure for 3D indoor navigation should be human-centered, semantic-based and intelligent, based on ontological knowledge representation and hybrid location modeling. Such architecture for the semantic-based 3D indoor navigation is depicted as Figure 1. There are five important parts in the architecture
31、, namely building blueprints, indoor navigation ontology, context awareness, 3D indoor network, BIM model. By considering the geographic characteristics of the building blueprints, indoor navigation ontology and context awareness, 3D indoor network model is automatically generated, followed by the b
32、est route computing and semantic links with BIM model. Figure 1: Architecture for BIM Information-supported, Semantic-based Indoor Navigation LI Yuan; HE Zizhang - 3D Indoor Navigation, 44th ISOCARP Congress 2008 5 Two key issues within the architecture will be further discussed in this paper, i.e.,
33、 information from BIM and topological elements for network analysis. 3 Information from BIM BIM, Building Information Modeling, is the next generation of CAD for the building industry. BIM means working within a 3D model, via an intelligent database, that contains all information for the following:
34、circle6 Design decision making circle6 Production of accurate construction documents circle6 Prediction of performance factors (i.e. energy consumption, load calculations, etc.); circle6 Cost-estimating, and design scenario planning circle6 Construction planning. The key to BIM is the “I” in the mid
35、dle: Information. BIM is centered on the development of a single project database that contains complete project data, both graphical and non-graphical. That includes all architectural and structural information as well as electrical and mechanical systems and other “real-world” data. The most impor
36、tant characteristics insides BIM models, different with commonly-used CAD models, are from two aspects: 3D information and semantic information. The 3D information will be automatically derived from Building Information Models without any extra efforts to build a 3D model. That is to say, flexible 3
37、D models and 3D scenarios can be automatically derived from the BIM model according to our dynamical needs. The rich semantic information contained within BIM like thickness, material, direction of opening, height, distance to facilities, etc. will be also inherited from the BIM models and readily a
38、vailable for use. However, for the specific purpose of indoor navigation, two kinds of information should be highlightening. 1) The building footprint of each floor within BIM. 2) Navigation-oriented semantic information within BIM The inner structure for a complex building (such as big mall) is oft
39、en complicated, and there are many small rooms inside each separated unit. From the functional perspective, in order to facilitate the derivation of the inner graph structure, the first step is to partition the building footprint of each floor into different kinds. An important kind is corridor, whi
40、ch is functioned as horizontal traversable links among rooms in the same floor. Rooms can be virtually linked with the corridor via doors or even windows. Room may also include sub rooms, which can be only linked with the corridor throught a room space. Stair is a kind of unique space, functioned as
41、 vertical traversable links of each floor. Stairs can be also virtually linked with the corridor via its exits. LI Yuan; HE Zizhang - 3D Indoor Navigation, 44th ISOCARP Congress 2008 6 Figure2: Building footprints and its functional partition Semantic information within BIM model is abundant, but ma
42、inly served for the purpose of architecture design or construction planning. Referring to the basic semantic information inside BIM, indoor navigation ontology is expanded, by considering the specific requirement for intelligent indoor navigation (aforementioned) and the available documents(Anagnost
43、opoulos et al. 2005): Figure 3: The Indoor Navigation Ontology circle6 User: different users have specific physical and perceptual capabilities. User profile is important in topological network construction, for example, physically handicapped people can travel from one floor to another only with el
44、evators. In emergency situation, they cannot escape a room from a window. Users location will be tracked as the start point in the network analysis. LI Yuan; HE Zizhang - 3D Indoor Navigation, 44th ISOCARP Congress 2008 7 circle6 Event: the concept of event is proposed to facilitate modeling anythin
45、g that prevents the passage of the user. Obstacle means the physical objects whose dimensions (width and height) block a corridor. It will unexpected occur in emergency situation when a wall collapsed. Closure refers to a closed door or non operating elevator, which need special equipment (such as d
46、oor keys) to make it traversable or need to wait for the right time to go through. circle6 Passage: it includes vertical passage and horizontal passage. Vertical passage connects corridors in different floor, such as elevator or stairway. Horizontal passage is comprised of corridor segment and inner
47、 door or inner window. Several corridor segments are integrated as a corridor. Inner door or inner window plays a supplementary role for corridor segment, in order to connect the neighboring room via a door or window. According to the functional difference inside a corridor segment, the node can be
48、divided into five kinds: CrossPoint, WindowPoint, DoorPoint, StairPoint and EndPoint. 4 Topological Elements for Indoor Navigation A good topological representation (graph) is the first step to a good navigation within a building. There are one or more numbers associated with each edge or node of a
49、graph, and these numbers might represent distances, costs, reliabilities, times, or other relevant parameters(Evans 2) a granting polygon maps always to an edge; 3) a connector section maps to a graph. However, these classifications should be well-balanced by its application domains. For example, a one-door room can be treated as an end section in normal indoor navigation but it may change as a connector section in emergency indoor navigation, because it is possible for a people escaping out into its neighboring room from a window. As thus, the extra topological LI Yuan; HE Zizhang - 3D In
