南水北调中线水源地面临着水质监测数据自动化程度不高、污染物扩散模拟效率较低、突发性水污染应急能力不足等困难,迫切需要开展数字化转型。基于数字孪生建设的总体要求,综合运用GIS、UE4、WebGL等新一代信息技术,建立了数字孪生水质平台,研发了水质浓度场静态可视化、污染物迁移扩散动态可视化和水质三维分层可视化模型等关键技术,初步实现了水质“四预”功能,切实提升了南水北调中线水源区水环境智能化、精细化管理水平,为推进饮用水水源地水质现代化提档升级提供了技术示范。

在排污口排查过程中单一采用正射影像，常常无法发现存在于树下、桥下的隐蔽排污口，为了解决该问题，本文以松花江干流区域为研究对象，提出了利用无人机正射影像、实景三维模型和水质反演参数混合解译的方法。首先利用水质参数异常信息确定重点排查区域，然后用正射影像进行大规模排查，标记出疑似排污口，同时利用倾斜摄影构建的实景三维模型对重点区域和疑似排污口进行解译。该方法有利于快速高效地查找隐蔽排污口，对河流和海洋水环境污染的追根溯源有重要意义。

In the process of sewage outlets investigation, it is often impossible to find hidden sewage outlets under trees and bridges by using orthophoto alone. In order to solve this problem, this paper selects the main stream area of Songhua River, and proposes a hybrid interpretation method using UAV orthophoto, 3D model and water quality inversion parameters. Firstly, the key investigation area is determined by the abnormal information of water quality parameters, and then the large-scale investigation is carried out by orthophoto to mark the suspected sewage outlets. At the same time, the real 3D model constructed by oblique photography is used to interpret the key areas and suspected sewage outlets. This method is conducive to the rapid and efficient search for hidden sewage outlets, and has great significance for tracing the source of river and marine water pollution.

三维GIS是当今乃至未来GIS技术的主要标志性内容之一，它突破了空间信息在二维地图平面中单调表现的束缚，为各行各业以及人们的日常生活提供了更有效的辅助决策支持。本文重点介绍了三维GIS的数据模型、数据库管理和可视化分析等关键技术及其研究进展，并以武汉市为例展示了三维GIS对城市立体空间的整体表达，为大城市、全市域的三维数字城市建设奠定了基础，最后探讨了在智慧城市建设与城市安全中三维GIS将发挥日益重要的时空信息承载引擎与空间智能技术支撑作用。

为提升MIKE FLOOD模型洪水风险展示中淹没区域细节的认知,动态反映发生溃口等险情时的洪水扩散过程,总结了洪水风险的现有表达手段,研究了洪水过程在3DGIS场景中的融合和表达方法,形成了一套可用于洪水风险三维动态推演的程序框架。以雄安新区内的主要河流南拒马河为例,基于MIKE11和MIKE21模型计算溃堤后的洪水过程,并以Open Scene Graph技术搭建三维GIS环境,在真实的三维地形地貌环境下进行洪水过程的动态推演分析。试验结果表明该方法相较于传统二维风险图方法具有细节表达和动态模拟上的优势,可以在宏观、中观和微观多个尺度对淹没过程进行模拟和表达,更加直观高效地反映洪水动态过程和淹没损失情况。

The aim of this research is to enhance our cognition on the details of inundation area in the flood risk display by MIKE FLOOD model, and reflect dynamically the flood propagation process when danger such as a breach occurs. We summarized the existing expression methods of flood risk, examined the fusion and expression methods of flood process in 3DGIS scene, and built a program framework for 3D dynamic derivation of flood risk. With the South Juma River in Xiongan New Area as a case study, we calculated the flood process after the dam break based on the MIKE Flood models, constructed a 3DGIS environment using the Open Scene Graph technology, and analyzed the flood process in a real three-dimensional topography. Result demonstrates that the presented method is prior to conventional 2D method in terms of detail expression and dynamic simulation. It can also describe the inundation process in multiple scales, and reflects the dynamic flood process more intuitively and efficiently.

使用Unity3D软件开发基于Microsoft HoloLens的UWP(Universal Windows Platform)有限元分析结果虚拟评审应用。利用Matlab进行编程完成三维实体静力有限元分析。为实现变形效果的可视化,提取有限元分析结果,生成VTK(Visualization Toolkit)格式文件,利用自制的文件转换器转换成.dae文件。在Unity3D软件中编写顶点着色器脚本实现片面模型的颜色显示和变形效果的可视化,最终发布UWP应用。实验结果表明：Matlab和Ansys Workbench有限元分析结果相吻合,基于HoloLens的有限元分析变形结果虚拟评审应用沉浸感强,交互性高,并可以推广到其他有限元分析应用领域。

An UWP application of virtual review of the finite element analysis based on Microsoft HoloLens is developed by using Unity3D software.<em> A set of programs are completed to realize three-dimensional solid static finite element analysis in Matlab. To realize the visualization of the deformation effect, the useful information of the finite element analysis result is extracted and exported to VTK file, then converted into DAE file. A vertex shader is written in Unity3D software to realize the color display and the visualization of deformation effect of one-sided model, and finally the UWP application is released to HoloLens.</em> The test results show that the finite element analysis results of Matlab and Ansys Workbench are consistent. The virtual review application of the finite element analysis deformation results based on HoloLens has strong immersion and high interactivity, and can be extended to other application fields of finite element analysis.