IfG.CC - Envisioning city digital twins in Indonesia

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From urban management concept to implementation

City digital twins are emerging as essential tools for urban management worldwide, including in Indonesia. In collaboration with the country’s Ministry of Agrarian Affairs and Spatial Planning, the Department of Geodetic Engineering at Universitas Gadjah Mada has developed a plan, design and prototype of a city digital twin for Surabaya, a major port city in Indonesia. This article explores the process, from 3D modelling to the integration of land parcel data using advanced modelling software and dynamic datasets. The prototype serves as a blueprint for creating 100 city digital twins across Indonesia by 2027, providing a transformative framework for urban planning and spatial data management.

As the boundaries between the real and virtual worlds continue to blur, digital twins (DTs) are increasingly being utilized in diverse sectors, including manufacturing, construction, energy, climate, transportation, healthcare and urban planning. In urban environments, this has led to the development of city digital twins (CDTs). In these contexts, 3D cadastre and spatial planning data can serve as a canvas for managing the ‘5Ps’ – people, planet, prosperity, peace, and partnership – associated with the Sustainable Development Goals (SDGs).

CDTs are virtual replicas of urban assets, which encompass infrastructure, human activities and environmental conditions. Many countries worldwide have adopted CDT initiatives for city analysis, simulation and predictive modelling. Acknowledging the significance of this technology, the Indonesian government – and especially the Ministry of Agrarian Affairs and Spatial Planning – has partnered with the Department of Geodetic Engineering at Universitas Gadjah Mada to develop a CDT prototype for Surabaya, Indonesia’s second largest city and home to a major port. This initiative serves as a foundational step toward a broader vision of creating 100 CDTs across Indonesia by 2027.

Indonesia’s land management system

The need for efficient land management has become increasingly urgent in Indonesia over recent decades. The near completion of systematic land registration for over 126 million land parcels in the country, known as PTSL, has established a strong foundation for the implementation of electronic certificates for new first registrations and data maintenance, which began in 2023. Integrating land rights with detailed spatial plans is also part of the vision to facilitate investments and improve business readiness. The country’s rapid population growth, particularly among productive age groups, supports its vision of ‘Indonesia Emas 2045’, which aims for sustainable development where prosperity and sustainability are achieved through good governance, including effective land governance.

Indonesia has recognized the need to transition from traditional 2D land administration to advanced 3D cadastre systems. For over two decades, the government has adopted standards and developed use cases for implementing the 3D cadastre concept, culminating in a national policy established in 2021. The regulation now allows for the first registration of 3D parcels above or below ground. However, Indonesia still faces challenges such as the lack of integration among overlapping, multipurpose business processes in 3D permits and spatial plans, as well as a deficit in standards and expertise in this area.

The transition from a traditional 2D land administration approach to a 3D approach involves moving from a conventional cadastre system to a multipurpose cadastre, allowing for the management of rights, restrictions and responsibilities (RRR) to encompass three dimensions: on the surface, above it and below it. This shift highlights the urgent need to develop digital twin technology in Indonesia. Such technology will aid in visualizing real-world updates related to RRR (including transactions, permits and developments) in relation to real-world urban phenomena (like traffic, pollution and movements), which can significantly impact spatial planning and land management outcomes, all supported by a robust land information infrastructure.

Developing digital twins in Indonesia

The development of DTs offers a valuable opportunity to tackle existing challenges. By integrating a variety of datasets, including land information, DTs align with Indonesia’s geospatial vision for efficiency and reliability under the ‘One Data, One Map’ initiative. This fosters interoperability and collaboration among institutions. This digital transformation contributes to the establishment of a unified national spatial framework, paving the way for the Digital Twin of Indonesia. The concept enhances decision-making processes by allowing policymakers to simulate and analyse urban issues. By visualizing these challenges within a collaborative digital twin, governments can proactively improve urban resilience by integrating 3D cadastral data, spatial plans and dynamic urban data.

Furthermore, Indonesia’s extensive and varied geography presents unique challenges for data collection and integration. To overcome these obstacles, technologies such as remote sensing, drones and Lidar mapping are increasingly being used to gather high-resolution spatial data, enhancing the CDT framework. These advanced technologies lay a solid foundation for precise modelling, addressing the complexities found in both urban and rural areas of Indonesia. When combined with cadastral systems, these tools ensure that 3D models are visually accurately aligned with administrative and legal standards.

3D modelling software

A CDT comprises two primary components: geometric data, which represents the 3D structure of city assets, and semantic data, which encapsulates the associated attributes and information. The geometric complexity of 3D models is commonly classified using the Level of Detail (LoD) standard, ranging from LoD0 (2.5D representation) to LoD4 (highly detailed models including the interior). For the Surabaya CDT prototype, an LoD2 model – featuring roof structures – was selected to balance detail and feasibility.

Two primary spatial data sources were utilized when modelling the city of Surabaya in 3D: orthophotos and point clouds. These datasets were derived from photogrammetry captured by uncrewed aerial vehicles (UAVs) and Lidar surveys, providing high-resolution and high-quality inputs for 3D modelling. The raw data underwent extensive processing to ensure accuracy and consistency. Various experiments were conducted to model LoD2 structures, with particular emphasis on capturing detailed roof geometries. Roof modelling required iterative refinement using advanced algorithms and manual corrections to achieve the desired precision.

The generation of 3D models has been an active area of research since the 1990s, employing manual, semi-automatic and automatic methods. Each method has its strengths and limitations. Several software tools were tested in this pilot project, including SketchUp, Blender, ArcGIS, Autodesk Revit, Autodesk InfraWorks, and City4CFD. Additionally, the GeoAI & HD map research team at Universitas Gadjah Mada developed Geo-CARTA and CASCADE3D, the desktop applications for generating LOD1 and LOD2-3D models automatically. Blender, ArcGIS, Autodesk Revit, and Autodesk InfraWorks were tested in different sample datasets. These tools were evaluated comprehensively to determine their suitability for modelling 3D cityscapes.

Prototype of a city digital twin in Indonesia

The resulting 3D city models were evaluated for completeness and geometric accuracy using field measurements. The case study focused on Surabaya employed CityGML, an Open Geospatial Consortium (OGC) standard for data interoperability, and was visualized using Cesium, a web-based platform. While the visualization was impressive, it initially lacked integration with real-world dynamics.

To address this, multiple sources of dynamic environmental data – including wind, air quality, temperature, UV index, humidity, live traffic and CCTV footage – were incorporated through APIs and local government data. This integration bridged the gap between the physical and digital realms, embodying the essence of a true digital twin. Notably, the system included a feature to update land parcel transactions (e.g. buy-sell, mortgages, or inheritance transfer) in real time, demonstrating a seamless connection between cadastral data and the CDT. This feature emphasizes the role of digital twins in land administration and land management. A real-world transfer and change of land rights or title also changes the corresponding data in the digital twin, connecting and integrating both worlds. The prototype includes a notification indicating a change of rights happening in the real world, such as sale or purchase of land.

The Surabaya CDT prototype serves as a benchmark for the Ministry of Agrarian Affairs and Spatial Planning to develop similar models for other Indonesian cities. It supports multi-LoD visualization, cross-sectional analysis and attribute filtering, addressing technical challenges in 3D city modelling and data integration. Additionally, a real-time simulation of transportation such as train movements has also been added to integrate more dynamic data. The prototype emphasizes user accessibility by providing an intuitive web interface, allowing stakeholders to interact with and analyse city data in real time.

The CDT prototype also incorporates features to simulate environmental conditions, enabling urban planners to predict and address issues like air pollution and flood risks. By analysing historical and real-time data, planners can implement targeted interventions to mitigate environmental challenges. Furthermore, the system supports collaboration among multiple stakeholders, facilitating data sharing and joint decision-making for sustainable urban development.

Ambition and vision

The CDT initiative aligns with Indonesia’s broader smart city strategy, which emphasizes sustainable urban development through advanced technology. Indonesia’s new capital, Ibu Kota Nusantara (IKN), exemplifies this vision, integrating smart transportation, data management and infrastructure while preserving local culture and green city principles. Digital twin technology plays a crucial role in achieving these goals.

The Surabaya CDT prototype represents a collaborative effort between Universitas Gadjah Mada and the Ministry, providing a standardized framework for scaling CDT implementation. By 2027, Indonesia aims to develop 100 CDTs, reflecting its commitment to leveraging digital technology for urban management and sustainability. Indonesia’s ambition extends beyond urban planning; it envisions CDTs as integral to disaster management, climate adaptation and economic forecasting. For instance, CDTs can model potential flood scenarios, enabling authorities to implement effective mitigation strategies. Similarly, the integration of renewable energy data into CDTs supports the transition to sustainable energy systems. By combining technological advancements with local expertise, the nation is well-equipped to overcome challenges and realize its vision of a digitally integrated and sustainable future.

Acknowledgements

The authors would like to express sincere gratitude to the Ministry of Agrarian Affairs and Spatial Planning (ATR/BPN) of Indonesia for the collaboration.

IfG.CC - Institute for eGovernment

Envisioning city digital twins in Indonesia

IfG.CC -
Institute for eGovernment