South Korean smart cities combine 3D digital models with GIS and BIM

Author: Linda Duffy

在世界范围内，地方政府正在推出智能城市/数字双胞胎项目，以支持经济刺激和旅游计划，并改善整体生活质量。最新的3D建筑模型和综合地理信息系统（GIS）数据以及建筑信息建模（BIM）数据合并，以创建建筑物内外的数字双胞胎以及周围的地形。实际上，现实世界将转换为精确的数字复制品，以促进对所有智能城市资产的分析，计划和管理。

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.

建立数字双胞胎

All4Land, a leading geospatial service provider in South Korea, has been building 3D digital models that include BIM and GIS data since 2014. To save time and reduce cost, All4Land collects oblique and LiDAR data simultaneously with itsLeica CityMapper机载映射传感器并快速处理数据Leica HxMap多传感器处理平台。导致的g 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数据和3D建筑模型，并集成建筑物所有者或政府机构提供的BIM数据。BIM数据是韩国新政府建设的必要条件，通常由第三方设计办公室生产。对于新建筑物，BIM通常在施工过程中和之后捕获，对于现有建筑物，它是通过使用3D扫描和原始设计数据的反向工程来确定的。

组合的CityMapper和HXMAP解决方案基于CityGML的详细信息1（LOD1）和LOD2提供自动处理，这是一种开放数据模型和基于XML的格式，用于存储和交换虚拟3D City Models。LOD3需要一些手动处理来表达大门和窗户等开放元素，而LOD4涉及的手动处理取决于室内细节的水平。

“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.”

为了将CityMapper数据与BIM数据相结合，All4land首先将GNSS测量得出的坐标分配给BIM数据，然后将BIM数据转换为3D构建模型，并将其与CityMapper数据合并。All4land开发了自己的专有软件，用于数据转换和坐标分配，并通过其Mapprime平台（可以集成室内和室外模型并提供数据可视化工具的WebGIS服务器，使3D模型可用。

CityMapper LiDAR Point cloud (Point density : 25 point/㎡)

Jeonju’s 3D model

In 2019, with its purchase of a highly efficient CityMapper aerial system and HxMap, All4Land became well-positioned to expand its 3D mapping services. Collecting data quickly is particularly important because of the unique limitations of aerial data capture in South Korea. Surrounded by the sea on three sides, cloud cover in South Korea frequently creates unfavourable weather conditions. In addition, it is difficult to get flight permission near military zones and security areas, therefore total flying days are quite limited. Under these circumstances, the CityMapper’s ability to capture orthophotos, oblique imagery and LiDAR all in one flight is advantageous.

“The CityMapper is an excellent solution for our projects ─ the added efficiency allows us to capture more data in a shorter period of time,” says Nam. “And HxMap streamlines the processing and modelling, which reduces the cost of building a digital twin.”

数字双胞胎概念的测试项目之一是在韩国西南部北耶拉省的旅游区Jeonju市。许多历史建筑，例如传统的村庄汉诺克（Hanok），吸引了游客，这座城市以其优秀的地区美食而闻名。最近，全场作为MAAS（移动性作为服务）的一部分引入了Digital Twin概念，以吸引游客并帮助他们使用电动自行车，电动踢板和其他运输工具在城市环游城市。

All4Land was selected to conduct two projects in Jeonju, first mapping an area 4 square kilometres (sq km) in size, including BIM for 20 buildings, followed by a 205 sq km project. The City of Jeonju and LX, the government cadastral organisation, are in the process of acquiring BIM data for all government-owned buildings in the larger area. Using CityMapper, aerial data capture of the large project took All4Land only two days, with an additional two to three months for data processing and 3D building modelling. The LOD3 outdoor data captured with the CityMapper were merged with indoor BIM data in the test area to create an LOD4 model of the real world.

“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.”

3D Building Model

聪明的城市是未来

There are approximately ten Smart City projects in South Korea today and the number is expected to increase. In addition to Jeonju, All4Land is working on the Virtual Seoul project for Seoul, South Korea, and a 3D geospatial project of Osan for the South Korea National Mapping Agency (NGII).

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.

“我们对CityMapper的性能和数据质量感到非常满意 - Nadir和Oblique Images和LiDAR非常好。我们还认为，Leica Geosystems提供的技术支持和培训计划是最好的。” Nam说。“ Leica Geosystems一直在支持客户，试图在整个运营和处理过程中一起找到更好的解决方案，这有助于我们在快速变化的行业中保持竞争力。”

CityMapper LiDAR Point cloud (Point density : 25 point/㎡)