Milan, Italy, a city renowned for its rich cultural heritage, iconic fashion scene, and vibrant economic activity, is also a hub of innovation. Beyond its historic landmarks like the Duomo and La Scala opera house, Milan stands at the forefront of urban transformation, merging tradition with cutting-edge technology. At the heart of this evolution is the digital twin concept—a comprehensive, data-rich simulation of the city that allows planners, engineers, and policymakers to model and evaluate future scenarios. Digital twins are not mere replicas of infrastructure; they incorporate dynamic simulations of human behavior and environmental factors, ensuring realistic and actionable insights. This innovative approach positions Milan as a trailblazer in smart city development, leveraging geospatial technologies to address urban challenges while setting a global benchmark for sustainable and adaptive urban management.
Geospatial Insights Shaping the Future of Urban Planning
The city of Milan is undergoing a major transformation with the creation of a comprehensive digital twin. Several leading geospatial companies have joined forces to realize this project, including CGR SpA, CycloMedia, Esri Italia SpA, and Servizi Informazione Territoriale (SIT Srl). The initiative also benefits from the analytical expertise of the Laboratory of Geomatics at the University of Pavia.
The project spans 1,575 km², encompassing Milan and its surrounding municipalities. The resulting digital twin incorporates a wide array of data types, from aerial imagery and Lidar point clouds to terrestrial mobile mapping data, producing 3D models and classified datasets for urban objects such as traffic lights and road signs.
Contributions of Crewed Airborne Surveying
A key component of the Milan digital twin project is the use of crewed airborne surveying, led by CGR SpA, one of the founding members of the European Association of Aerial Surveying Industries (EAASI). The company was responsible for acquiring and processing high-resolution geospatial data, forming the foundation of the city's 3D model.
CGR's pilots executed detailed flight plans to capture aerial imagery and LiDAR point cloud data across Milan. An advanced sensor, the Leica CityMapper-2, was used to collect data with sub-centimeter accuracy. Aerial images were captured with a resolution of 5 cm, providing detailed visuals of the cityscape. LiDAR data exceeded the project's initial requirement of 20 points per square meter, achieving an impressive average density of 55 points per square meter.
CGR's technical team processed the raw data using specialized software and automated techniques. Rigorous quality control measures ensured the accuracy and reliability of the final product. Horizontal accuracy was measured at 1.8 cm, while vertical accuracy reached 3.7 cm for LiDAR data. The seamless integration of aerial and ground-based datasets resulted in a Root Mean Square Error (RMSE) of 7 cm horizontally and 14 cm vertically.
The integrated dataset, comprising aerial imagery, LiDAR point clouds, and ground-based surveys, provides a comprehensive 3D model of the city. This digital twin enables urban planners, engineers, and policymakers to make informed decisions and simulate future scenarios.
CGR's expertise in geospatial technologies and its commitment to quality contributed to the successful development of Milan's digital twin.
To enhance the accuracy and depth of the digital twin, CycloMedia conducted mobile mapping surveys, focusing on areas inaccessible to aerial methods. The Laboratory of Geomatics at the University of Pavia played a crucial role in assessing the data quality and ensuring the reliability of both airborne and terrestrial datasets. Esri Italia SpA and SIT Srl contributed to data management and topographic surveys, rounding out a collaborative effort that combined expertise from multiple geospatial disciplines.
Impact on Urban Planning and Management
The Milan digital twin project offers significant practical applications, producing datasets and tools that support decision-making across various urban sectors. Key deliverables include:
- True Orthophotos (RGB and CIR): High-resolution imagery providing detailed views of the city.
- Classified Lidar Point Clouds: Categorized into 11 urban object types, such as buildings, vegetation, and water.
- 3D Models: DSMs and DTMs enabling simulations and predictive analyses.
These datasets are already proving instrumental in infrastructure maintenance, traffic optimization, and environmental monitoring, offering insights into climate adaptation strategies and urban resilience planning.
Airborne data, a cornerstone for digital twins
The Milan digital twin project exemplifies the transformative potential of geospatial technologies in shaping smarter, more resilient cities. Several EAASI companies played vital roles in this initiative, highlighting the strength of collaboration within the aerial surveying industry. The Leica CityMapper-2 sensor, developed by Leica Geosystems, part of Hexagon, provided the high-resolution imagery and LiDAR data fundamental to the project’s success. Esri Italia also made critical contributions to data management, ensuring seamless integration and usability of the extensive datasets. These partnerships underscore the importance of collaboration in achieving innovative solutions for urban challenges.
As cities increasingly turn to digital twins for planning, infrastructure management, and environmental resilience, crewed airborne data remains a cornerstone of these efforts. With its unparalleled ability to capture high-resolution data over extensive areas in a timely and precise manner, crewed airborne surveying continues to deliver competitive advantages that remain unmatched by other platforms. Milan’s digital twin serves as a benchmark for what is achievable when advanced technology, expertise, and cooperation converge, paving the way for a more sustainable and data-driven future.
Milan joins the ranks of several European cities at the forefront of developing digital twins. Some others European cities are showcasing the power of this technology:
- Helsinki, Finland: Their digital twin, evolved into an Energy and Climate Atlas, helps achieve carbon neutrality goals through granular data analysis.
- Barcelona, Spain: Barcelona has been developing a digital twin for its smart city initiatives. The city's digital twin focuses on improving energy efficiency, waste management, and urban mobility. It integrates data from various sources to create a comprehensive model of the city's infrastructure and services
- Tampere, Finland: Pioneering "cityverse" concepts, Tampere uses digital twins for pedestrian services and innovative citizen engagement in urban design.
- Rotterdam, Netherlands: has developed a homegrown digital twin to improve urban planning and infrastructure management. The platform integrates real-time data to simulate scenarios, optimize city services, and enhance sustainability initiatives.
This trend extends across Europe, with over 135 Local Digital Twin initiatives underway.
