By Wang Zhe, People’s Daily

With a simple scroll of the mouse, the city of Qingdao, east China’s Shandong province, comes vividly into view – high-resolutionbuildings rise sharply, their intricate details clearly rendered.

At his workstation, Hu Zhenbiao, chief systems architect at the Qingdao Institute of Survey and Mapping, introduced a city-scale 3D simulation platform: a full-scale digital twin of the city.

Real-scene 3D modeling has become a vital strategic resource and production element in the development of digital cities and the broader digital economy. By offering accurate, spatial-temporal depictions of urban spaces, these technologies provide vital insight into the dynamics of modern city life, infrastructure, and ecosystems.

The platform, officially launched in March 2021 under the leadership of the Qingdao Institute of Survey and Mapping, represents a landmark in urban digitization.

“Behind this platform lies more than six months of aerial photography, the processing of millions of images, and the 3D modeling of hundreds of thousands of buildings,” Hu explained.

Qingdao’s varied topography – marked by hilly terrain and dramatic elevation changes – necessitated the use of oblique aerial imaging to capture raw imagery and build an accurate 3D model.

For this phase, the project team deployed manned fixed-wing aircraft equipped with 150-megapixel, five-lens oblique aerial cameras. The aerial survey covered the entire urban area, achieving a ground resolution of 15 centimeters and maintaining more than 70 percent image overlap to maximize accuracy.

Hu noted that certain structural details – such as eaves and building undersides – were sometimes difficult to capture due to limited aerial angles, requiring on-site supplemental photography. “We used a combination of hybrid restoration and modeling techniques to accurately reconstruct the structures,” he said, pointing to the Qingdao International Conference Center on his screen. “Those eaves, for example, were recreated using 3D modeling.”

In March 2022, following expert review, the project was officially launched for citywide application. Today, the platform covers Qingdao’s entire land area – 11,000 square kilometers – as well as 800 kilometers of coastline, 49 bays, and seven inhabited islands.

“Fire reported on the eastern slope. Please respond immediately,” came the voice over the radio at the emergency command center in Qingdao’s West Coast New Area.

Qi Degang, deputy headof the area’s emergency management bureau, responded quickly. “The nearest water source is Reservoir No. 37 in Lingshanwei, about 700 meters away.”

This exchange occurred during a forest fire response drill on Xiaozhu Mountain. Displayed prominently on a large screen in the command center was a real-time, 3Dforest fire map – showing the fire’s location, affected area, and smoke direction.

“Our drones send back live footage, which is directlyfed into the 3D platform,” explained Mu Kun, head of forest fire response at the emergency management bureau.

A new call came in: “There’s a fork ahead – what’s the fastest route?”

Mu quickly zoomed in, selected a mountain trail and charted a path for the responders. “This trail is only one meter wide. Rescuers will have to go on foot. Elevation gain: 200 meters.”

“The 3D model allows us to act with greater speed and precision,” Qi added. “It helps us identify access routes, calculate burn areas, and direct field personnel efficiently.”

To date, Qingdao’scity-scale 3D simulation platform has been shared with over 60 municipal departments. It supports more than 100 key functions, including disaster prevention and mitigation, urban planning, social governance, and urban renewal. The platform also underpins over 70 digital government service applications and records nearly 100 million uses annually.

“Compared to traditional 2D maps, 3D modeling offers greater realism, dimensionality, and accuracy,” said Xue Hongli, deputy head of the Qingdao Bureau of Natural Resources and Planning. “It creates a holographic digital twin of the physical world, providing strong spatial support for fine-grained urban management.”

Xue emphasized that cities are constantly changing and 3D mapping must evolve in tandem to capture these transformations with fidelity.

At the bureau’s headquarters, staff members examined two versions of a digital model for a former mining site in Qingdao’s West Coast New Area. The comparison revealed tangible signs of ecological restoration – more vegetation and a gentler slope.

Qingdao is home to 898 legacy mine sites. In the past, inspectingthese sites required a full month of on-the-ground efforts. Now, with the help of the 3D model, the same work takes just five days. Since 2023, the city has carried out annual temporal updates to the city-scale 3D simulation platform, enabling it to track urban changes with precision and support data-driven analysis and evidence-ba