三维场景树荫模拟与量化——以城市街道为例  

Simulation and Quantification of Tree Shade in Three-Dimensional Scenes:A Case Study of Urban Street

作　　者：苏宏霖 唐丽玉[1,2,3] 陈季委 高继淼 袁跃辉 SU Honglin;TANG Liyu;CHEN Jiwei;GAO Jimiao;YUAN Yuehui(Key Laboratory of Spatial Data Mining&Information Sharing of Ministry of Education,Fuzhou University,Fuzhou 350108,China;National Engineering Research Center of Geospatial Information Technology,Fuzhou University,Fuzhou 350108,China;The Academy of Digital China(Fujian),Fuzhou 350108,China)

机构地区：[1]福州大学空间数据挖掘与信息共享教育部重点实验室,福州350108 [2]福州大学地理空间信息技术国家地方联合工程研究中心,福州350108 [3]数字中国研究院(福建),福州350108

出　　处：《地球信息科学学报》2024年第11期2493-2505,共13页Journal of Geo-information Science

基　　金：国家自然科学基金项目(42371482)。

摘　　要：树荫是城市区域夏季降温的重要资源之一,对树荫资源的量化可为城市极端高温天气的风险预警提供帮助。现有估算树荫资源的方法中,实测法耗费时间且成效较低,影像识别法难以精确反映树荫的时空变化,本文提出一种基于三维场景的树荫模拟与量化方法。通过三维重建技术模拟城市街道场景,区分并标识地理实体模型的类型;根据太阳几何位置参数信息,构建与实地场景同步的光照环境;根据光线直线传播和阴影形成原理,利用射线求交算法判断太阳光线与场景三维模型的遮挡情况,生成树荫并与其他地物阴影进行区分;量化树荫面积、树荫覆盖时长等数据,并在三维场景中进行可视化效果呈现。通过与无人机拍摄的阴影对比验证,相对误差区间为3.35%~13.27%,平均相对误差为9.29%,该方法在树荫资源估算方面有应用潜力。同时,以城市街道场景为例,模拟量化了不同空间朝向、不同树种、不同樟树生命周期的街道树荫资源情况并进行相应分析。该方法可以模拟任意时刻现实的和虚拟的(未来的或规划的)情景的阴影资源的时空分布情况,且可以进行分类统计,为城市规划管理提供参考,为城市树木降温效应分析提供基础数据。Tree shade is an important resources for mitigating the effects of extreme heat in urban areas.Quantifying the extent of tree shade resources can assist in the prediction and risk assessment of high temperatures in cities.Among the existing methods for estimating tree shade resources,the measured method is time-consuming and ineffective,while the image identification method is difficult to accurately respond to the spatial and temporal changes of tree shade.In this paper,a method was proposed for simulating and quantifying tree shade based on a three-dimensional(3D)scene.We simulated the urban street scene by employing 3D reconstruction technology,distinguished different geographic entity models,utilising the sun's geometric position parameter and construct the corresponding lighting environment,and the shade in 3D scene was simulated according to the principle of linear propagation of light and shadow.The formation of tree shade is determined through the use of a ray intersection algorithm,which allows for the differentiation of sun rays within a 3D model of the shading situation.This process enables the generation and classification of tree shade,which can then be distinguished from shadows cast by their features.The attributes of tree shade(e.g.,shade area and shade coverage duration facilitates)can be quantified and visualized in the 3D scene for intuitive representation.A comparison and verification of the shadows taken by the Unmanned Aerial Vehicle(UAV).The results of relative error range from 3.35%to 13.27%,with an average relative error of 9.29%.This method is potential for the estimation of shade tree resources.In addition,a case of shade resources of trees in an urban street scene was simulated and quantified,taking into account their spatial orientation,species and life cycle.The method enables the simulation of the spatial and temporal distribution of shadow resources for real and virtual scenarios(both future and planned)at any given moment.It can be classified and counted,thereby providing the pote

关 键 词：虚拟地理环境 城市绿地 树荫 三维模拟 遮荫效应 

分 类 号：TU985.12[建筑科学—城市规划与设计] TP391.41[自动化与计算机技术—计算机应用技术]