South Korean smart cities combine 3D digital models with GIS and BIM
Leica CityMapper和HXMAP降低了建立数字双胞胎的时间和成本。
作者：琳达·达菲（Linda Duffy）
Around the world, local governments are rolling out Smart City/Digital Twin projects to support economic stimulation and tourism programs and to improve the quality of life overall. Up-to-date 3D building models and comprehensive Geographic Information Systems (GIS) data, along with Building Information Modelling (BIM) data, are combined to create a digital twin of the inside and outside of buildings and the surrounding topography. In effect, the real world is converted into an exact digital replica to facilitate analysis, planning and management of all smart city assets.
The primary goal behind 3D virtual cities is to reduce and manage problems typically found in urban areas by conducting simulations and analysis on digital twins and using the results to improve conditions. In addition, big data captured with Internet of Things (IoT) sensors, closed-circuit television (CCTV), security cameras, etc., provide insight into specific locations. The South Korean government started its Smart City/Digital Twin program in 2017 to address various issues, such as traffic, crime, environmental pollution, efficient energy management, urban planning, disaster management, and redevelopment. By analysing the virtual cities and associated big data, governmental entities are better equipped to address areas of concern.
Building a digital twin
All4land是韩国领先的地理空间服务提供商，一直在建立3D数字模型，包括自2014年以来，包括BIM和GIS数据。为了节省时间并降低成本，All4land同时收集倾斜和激光雷达数据。Leica CityMapperairborne mapping sensor and quickly processes the data withLeica HxMap, a multi-sensor processing platform. The resulting 3D models are enhanced with GIS data, such as vector maps of utilities, telecommunication, or transportation infrastructures, to support in-depth analysis. The external shapes of buildings are made from CityMapper data and the internal shapes are made from 3D scanning data, design data and BIM data.
All4Land负责创建GIS数据and 3D building models and integrating BIM data provided by the building owner or a government agency. BIM data is mandatory for new government construction in Korea and is normally produced by a 3rd party design office. For new buildings, BIM is typically captured during and after the construction process, and for existing buildings it is established by reverse engineering with 3D scanning and original design data.
The combined CityMapper and HxMap solution provides automatic processing at Level of Detail 1 (LOD1) and LOD2 based on CityGML, an open data model and XML-based format for the storage and exchange of virtual 3D city models. LOD3 requires some manual processing to express open elements like gates and windows, and LOD4 involves manual processing that depends on the level of indoor details.
“There are powerful functions in HxMap, especially in simultaneous aerial triangulation processing for multiple cameras, and efficient 3D modelling from both image and LiDAR data,” says Sangkwam Nam, managing director, All4Land. “HxMap also supports processing tasks such as sensor calibration, automatic point matching, line-to-line registration, building generation and many more. All of these were previously tedious manual tasks that can now be run automatically within the HxMap workflow.”
To combine CityMapper data with BIM data, All4Land first allocates coordinates derived by GNSS surveying to the BIM data, then converts the BIM data to 3D building models and merges them with CityMapper data. All4Land developed its own proprietary software for data conversion and coordinate allocation and makes the 3D models available through its MapPrime platform, a WebGIS server that integrates indoor and outdoor models and provides data visualisation tools.
全球的3D模型
在2019年，All4land购买了高效的CityMapper空中系统和HXMAP，All4land变得良好地扩展了其3D映射服务。由于韩国航空数据捕获的独特局限性，尤其很重要。韩国的云覆盖物被海洋包围着，经常造成不利的天气条件。此外，很难在军事区域和安全区附近获得飞行许可，因此总飞行日非常有限。在这种情况下，CityMapper捕获正射，斜图像和LIDAR的能力在一次飞行中都是有利的。
Nam说：“ CityMapper是我们项目的绝佳解决方案 - 增加的效率使我们能够在较短的时间内捕获更多数据。”“并且HXMAP简化了处理和建模，从而降低了建造数字双胞胎的成本。”
One of the test projects for the Digital Twin concept was in the city of Jeonju, a tourist area in North Jeolla Province in southwestern South Korea. Many historic buildings, such as the traditional village called Hanok, attract visitors, and the city is known for its excellent regional cuisine. Recently Jeonju introduced the Digital Twin concept as part of MaaS (Mobility as a Service) to attract tourists and help them travel around the city using electric bicycles, electric kick boards, and other transportation.
All4land被选中在全都进行两个项目，首先绘制一个面积为4平方公里（平方公里）的区域，其中包括BIM的20座建筑物，然后是205平方公里的项目。政府会员组织Jeonju和LX市正在为较大地区的所有政府拥有的建筑物获取BIM数据。使用CityMapper，该大型项目的航空数据捕获仅花了两天时间，而数据处理和3D建筑建模也有额外的两到三个月。与CityMapper捕获的LOD3室外数据与测试区域中的室内BIM数据合并，以创建现实世界的LOD4模型。
“Digital twins are helpful for many applications,” Nam stated. “For example, before planning a new building in a downtown area, the simulation model is utilised to analyse the 360-degree view, visibility range, solar rights, privacy issues, etc. This uncovers any potential conflict with existing buildings. The development plan can be revised and improved in the early stages, which saves money in the long run.”
Smart cities are the future
当今韩国大约有十个智能城市项目，预计数量将增加。除全地外，All4land还在为韩国首尔市的虚拟首尔项目和韩国国家地图局（NGII）的3D地理空间项目（NGII）致力。
South Korean Smart Cities focus on vitalisation of the local economy based on smart mobility, demographics, tourism, and other factors. Government organisations use the 3D building models to analyse options and opportunities to support decision making. In the future, All4Land expects the MapPrime platform to be open to commercial companies for the management of facilities, parking, sightseeing, etc.
The expanded use of digital twins relies on efficient collection of data and highly automated processing to keep costs reasonable. Leica CityMapper, and the more recent CityMapper-2, are high-performance urban mapping sensors ideal for fast digitisation of cities and urban environments. The hybrid oblique imaging and LiDAR solutions, paired with the HxMap processing platform, together provide high productivity and fast turnaround.
“We are very satisfied with the CityMapper’s performance and data quality ─ the nadir and oblique images and LiDAR are excellent. We also feel that technical support and training programs offered by Leica Geosystems are the best,” says Nam. “Leica Geosystems keeps supporting customers, trying to find better solutions together during the entire process of operation and processing, and that helps us stay competitive in a rapidly changing industry.”
