Voxel-Based Visibility Analysis for Safety Assessment of Urban Environments

Aleksandrov, Mitko; Zlatanova, Sisi; Kimmel, Laurence; Barton, Joseph E.; Gorte, B.G.H.

doi:10.5194/isprs-annals-iv-4-w8-11-2019

Cited by 18 publications

(10 citation statements)

References 22 publications

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“…While appropriate for realistic visualisation, Boundary representation can fall short in performing spatial operations as volume validation and computation. Therefore, for many applications Spatial Occupancy Enumeration (e.g., voxels [125,126]) can be seen as alternative [127,128]. There is no strict pattern which geometric representation is employed in different disciplines.…”

Section: Spaces Representationmentioning

confidence: 99%

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

Zlatanova¹,

Yan²,

Wang

et al. 2020

IJGI

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In spatial science and urban applications, “space" is presented by multiple disciplines as a notion referencing our living environment. Space is used as a general term to help understand particular characteristics of the environment. However, the definition and perception of space varies and these variations have to be harmonised. For example, space may have diverse definitions and classification, the same environment may be abstracted/modelled by contradicting notions of space, which can lead to inconsistencies and misunderstandings. In this paper, we seek to investigate and document the state-of-the-art in the research of “space” regarding its definition, classification, modelling and utilization (2D/3D) in spatial sciences and urban applications. We focus on positioning, navigation, building micro-climate and thermal comfort, landscape, urban planning and design, urban heat island, interior design and planning, transportation and intelligent space. We review 147 research papers, technical reports and on-line resources. We compare the presented space concepts with respect to five criteria—classification, boundary, modelling components, use of standards and granularity. The review inventory is intended for both scientists and professionals in the spatial industry, such as companies, national mapping agencies and governments, and aim to provide a reference to better understand and employ the “space” while working across disciplines.

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Section: Spaces Representationmentioning

confidence: 99%

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

Zlatanova¹,

Yan²,

Wang

et al. 2020

IJGI

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“…In terms of navigation domains, 3D indoor navigation, 3D seamless indoor/outdoor navigation, path computation considering movable obstacles, etc. have a thirst for fine-grained 3D spatial information (Liu and Zlatanova, 2015;Wang and Zlatanova, 2016;Aleksandrov et al, 2019;Yan et al, 2019;. Even in urban environments, the sort of spatial information plays a significant role, such as visibility analysis and safety assessment (Aleksandrov et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…have a thirst for fine-grained 3D spatial information (Liu and Zlatanova, 2015;Wang and Zlatanova, 2016;Aleksandrov et al, 2019;Yan et al, 2019;. Even in urban environments, the sort of spatial information plays a significant role, such as visibility analysis and safety assessment (Aleksandrov et al, 2019). Regarding the 3D modelling approaches for indoor environments, Building Information Modelling is commonly used to obtain 3D spatial information since it contains and depicts 3D geometry, topological relations, semantic information and properties of indoor environments (Abou Diakité and Zlatanova, 2016;Wu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

3d Indoor-Pedestrian Interaction in Emergencies: A Review of Actual Evacuations and Simulation Models

Xie

Zlatanova

Lee

2022

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Pedestrian motions and behaviours in evacuations are compactly interrelated indoor environments. According to how pedestrians interact with indoor environments in three-dimensional (3D) space, 3D indoor-pedestrian interaction is defined as five sorts of specific pedestrian motions, i.e., stepping over, crawling, bent-over walking, jumping over and climbing over. However, the occurrence and prevalence of the interaction in actual evacuations have not been identified, and the degree of effectiveness and practicality of the evacuation simulation models regarding the interaction is yet to be evaluated. Understanding the interaction and simulating it realistically bring apparent benefits to support informed policymaking, building safety optimization and emergency relief efforts. Therefore, this article aims to review the 3D indoor-pedestrian interaction in actual evacuations, assess the capabilities and performance of the evacuation simulation models for the interaction, and identify their limitations and challenges for future work. We first demonstrate that the fundamental relationships between the decision-making process of a pedestrian, object distance and object size/shape in 3D space are unclear yet, and the scarcity of experimental investigation for local routes choices and each motion is vast. Subsequently, the comparisons between Social Force models, Cellular Automata models and Agent-based models suggest that these microscopic models can yield the 3D indoor-pedestrian interaction, but the height dimension of 3D space is not explicitly considered during the evacuation modelling. This article is expected to advance the understanding of pedestrian evacuations in 3D space, ultimately improving pedestrian safety in indoor environments.

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“…Voxel-based representations are used in many application domains. In computer graphics, voxels are used for fast ray tracing [1], voxelisation of surfaces and solids [2,3], shadow [4] and visibility analysis [5][6][7]. These are mostly focused on fast-real time visualisation and therefore aiming at visualising only visible voxels.…”

Section: Introductionmentioning

confidence: 99%

Voxelisation Algorithms and Data Structures: A Review

Aleksandrov

Zlatanova

Heslop

2021

Sensors

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Voxel-based data structures, algorithms, frameworks, and interfaces have been used in computer graphics and many other applications for decades. There is a general necessity to seek adequate digital representations, such as voxels, that would secure unified data structures, multi-resolution options, robust validation procedures and flexible algorithms for different 3D tasks. In this review, we evaluate the most common properties and algorithms for voxelisation of 2D and 3D objects. Thus, many voxelisation algorithms and their characteristics are presented targeting points, lines, triangles, surfaces and solids as geometric primitives. For lines, we identify three groups of algorithms, where the first two achieve different voxelisation connectivity, while the third one presents voxelisation of curves. We can say that surface voxelisation is a more desired voxelisation type compared to solid voxelisation, as it can be achieved faster and requires less memory if voxels are stored in a sparse way. At the same time, we evaluate in the paper the available voxel data structures. We split all data structures into static and dynamic grids considering the frequency to update a data structure. Static grids are dominated by SVO-based data structures focusing on memory footprint reduction and attributes preservation, where SVDAG and SSVDAG are the most advanced methods. The state-of-the-art dynamic voxel data structure is NanoVDB which is superior to the rest in terms of speed as well as support for out-of-core processing and data management, which is the key to handling large dynamically changing scenes. Overall, we can say that this is the first review evaluating the available voxelisation algorithms for different geometric primitives as well as voxel data structures.

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Voxel-Based Visibility Analysis for Safety Assessment of Urban Environments

Cited by 18 publications

References 22 publications

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

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

3d Indoor-Pedestrian Interaction in Emergencies: A Review of Actual Evacuations and Simulation Models

Voxelisation Algorithms and Data Structures: A Review

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