# Voxel-Based Navigation: A Systematic Review of Techniques, Applications, and Challenges
###### Abstract  
In recent years, navigation has attracted widespread attention across various fields, such as geomatics, robotics, photogrammetry, and transportation. Modeling the navigation environment is a key step in building successful navigation services. While traditional navigation systems have relied solely on 2D data, advancements in 3D sensing technology have made more 3D data available, enabling more realistic environmental modeling. This paper primarily focuses on voxel-based navigation and reviews the existing literature that covers various aspects of using voxel data or models to support navigation. The paper first discusses key technologies related to voxel-based navigation, including voxel-based modeling, voxel segmentation, voxel-based analysis, and voxel storage and management. It then distinguishes and discusses indoor and outdoor navigation based on the application scenarios. Additionally, various issues related to voxel-based navigation are addressed. Finally, the paper presents several potential research opportunities that may be useful for researchers or companies in developing more advanced navigation systems for pedestrians, robots, and vehicles. voxel models; route planning; navigation; 3D GIS +
Footnote †: journal: Geo-Informat  
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safety of path planning. However, constructing high-precision environmental models poses numerous challenges, including accurately representing complex 3D spaces, dynamically updating environmental information, and managing and processing large-scale data with significant resource demands. One promising approach is the use of voxels, as illustrated in Figure 1. Voxel, short for \"Volume Pixel\", can be seen as the 3D counterpart of a pixel in a 2D image. As a fundamental unit in 3D space, voxels are defined on a regular 3D grid and are used to represent spatial positions and their associated properties. Typically, a voxel is represented by its center point or a corner point rather than being directly stored as a geometric cube. Each voxel is associated with one or more values that describe measurable attributes or independent variables of real-world objects or phenomena, such as density, color, or other characteristics [9; 10; 11]. Table 1 compares several 3D-representation methods for navigation. As shown in the table, compared to other methods, voxel models not only support complex 3D path-planning algorithms but also allow for flexible resolution adjustments and easy dynamic information updates, adapting to various application scenarios. Moreover, their structured data format simplifies model processing, further enhancing their potential and value in navigation applications. Currently, there is still a lack of comprehensive summaries and discussions on voxel-based navigation, as well as on their advantages and disadvantages in practical applications. Therefore, this paper provides a systematic review of the existing applications of voxel-based modeling in research related to navigation and path planning, focusing on the characteristics, strengths, and weaknesses of voxel-based path planning. The contributions of this work are as follows:  
* We provide a detailed discussion of the history and characteristics of voxel-based navigation. To the best of our knowledge, this is the first review focusing on voxel-based navigation. * We review the key technologies required for voxel-based navigation, considering four critical aspects: voxel modeling, voxel segmentation, voxel analysis, and voxel management. * We investigate various applications of voxel-based navigation and discuss their advantages and disadvantages in these applications. * Based on the above, we analyze the potential and limitations of voxel-based navigation. The remainder of this paper is organized as follows: In Section 2, we describe the methods used in this literature review. In Section 3, we discuss the advantages of voxel-based representation.