An Extraction Approach of the Top-Bounded Space Formed by Buildings for Pedestrian Navigation

Abstract

<p><strong>Abstract.</strong> The navigation of pedestrians can be regarded as their movements from one unoccupied space to another unoccupied and connected space. These movements generally occur in three types of environments: indoor, outdoor, and semi-bounded (top-bounded, and/or side-bounded) spaces. While the two former types of spaces are subject to most of the attention, the latter (semi-bounded) also presents a valuable impact on the navigation behaviour. For example, top-bounded environments (e.g. roofs, shelters, etc.) are very popular for pedestrian navigation since a top structure can offer protection from harsh weather, rain, or strong sun. However, such semibounded spaces are completely missing in current navigation models and systems. This is partly explained by the fact that modelling the space, which is by defining a three-dimensional boundless and extensible component (mainly out of the indoor environment), is a very challenging task. In this paper, we propose a structure-based approach for top-bounded space extraction in the built environment, relying on 3D models. Thanks to the rapid expansion and availability of 3D city models, our approach can help to account for such type of spaces in 3D pedestrian navigation systems.</p>

Spaces in Spatial Science and Urban Applications—State of the Art Review

“…The research presented above is based on examples or human notions to clarify space. Reference [19] made the first attempt to develop a framework for formally distinguishing between spaces, depending on their construction characteristics and methodology to define cells. The authors defined space as "hollow (unoccupied)", constrained by some partial (or complete) physical boundaries, where human activities can take place.…”

“…Combination of imaginary and physical boundaries can be used to partition spaces for leisure, drying laundry, growing plants [4], sheltering from the sun and wind [5] and similar activities [6][7][8]. Cells have been introduced in different disciplines related to urban applications ( Figure 1, such as positioning and navigation [9][10][11][12][13][14][15][16][17][18][19][20][21] (indoor [22][23][24][25][26][27][28][29], outdoor [30][31][32]), building micro-climate and thermal comfort [4,[33][34][35][36][37][38], landscape, urban planning and design [39][40][41][42][43][44], urban heat island [45][46][47], interior design [48][49]<...>…”

Finding outdoor boundaries for 3D space‐based navigation

“…In previous research (Yan, Diakité, & Zlatanova, ; Yan et al., ), space is categorized as indoor (completely bounded), outdoor (completely unbounded), or semi‐bounded (top/side‐bounded); see Figure . Furthermore, spaces are defined as 3D volumes bounded by three basic elements (boundaries): top (upper boundary), side (surrounding boundary), and bottom (lower boundary).…”

A generic space definition framework to support seamless indoor/outdoor navigation systems

“…In the current research, four classifications of space are given: indoor, outdoor, semi‐indoor and semi‐outdoor space. While there is agreement on indoor and outdoor space, semi‐indoor semi‐outdoor spaces are ill‐defined and contradictory (Yan, Diakite, & Zlatanova, ).…”

“…If the space has sides and tops at the same time, no matter what closures they have, the boundaries of the space can be determined by them (see, for example, the sI‐spaces in Figures b, d, and e). Otherwise, if the space has only a top, the sides can be estimated by projecting the top on the ground (see Figures a–c and e–g; see also Yan et al., ) if the space has sides only, a virtual top can be estimated by a predefined maximum height adapted to the needs of the agents, for example, 3 m in this case (see boundaries of the sO‐spaces in Figures d, e, g, and i). A possible way to get the outdoor spaces is to rely on the geometry of the footprints in data models, and then the necessary height can also be estimated (see the O‐spaces in Figures h and j).…”