Urban Digital Twins Interoperability Pilot: Call for Participation (CFP)

1. Introduction

The Open Geospatial Consortium (OGC) calls for proposals to participate in an Urban Digital Twin Interoperability Pilot (UDTIP), sponsored by the Korea Land and Housing Agency. Over half of the world’s population lives in cities. Innovations in the planning, design and management of urban environments are essential to enable their residents to live healthier, safer, happier lives and shape inclusive, sustainable, resilient urban futures. Geospatial information and technologies are essential building blocks for innovations across applications from promoting active transport, to urban power grid monitoring, to planning an infrastructure upgrade. Urban Digital Twins provide an integrated platform for up-to-date location-aware data, process-based modeling, and visualization, creating a rich environment for collaborative, data-driven work in urban contexts. The Open Geospatial Consortium (OGC) Urban Digital Twin Interoperability Pilot (UDTIP) will build a consortium of partners to identify opportunities to improve geospatial data interoperability within Urban Digital Twins to meet the needs of the diverse organizations engaged in building present and future urban communities.

2. Pilot Project Background

A digital twin is in essence a 6D (3 spatial axes, one phenomenon time axis, one valid time axis, one "what-if" axis) geospatial model of a portion and aspect of the biophysical-social world combined with one or more workflows that set / update the objects and attributes of the model. The real-world interfaces (sensors, surveys) may or may not themselves form part of the model. The available output of the digital twin is any information contained within the model itself.

As a technological ideal, digital twins present a number of challenges, particularly in terms of spatial information interoperability. Two challenges in particular have been addressed but not yet solved through OGC initiatives and standardization:

  1. A digital twin requires the integration of persistent information, for example digital models of buildings and urban infrastructure, with dynamic information such as the trajectories of people and vehicles or environmental properties such as noise or air quality. The 3D-IoT Pilot conducted by OGC with support from LH explored several approaches to accomplishing this integration through the use of OGC standards and interoperability architectures. The persistent and dynamic information elements typically derive from different sources, managed by different communities using different systems. Timely integration of these elements is both a technical and semantic challenge, for example assuring that a given sensor is providing accurate and timely estimates for a particular property of a particular persistent feature such as a street intersection or building hallway.

  2. It is not feasible for a single digital twin to represent all of the appearance and behavior of the real world everywhere. In order to provide a broader and more accurate representation, it is necessary for individual digital twin models and systems to interoperate, to exchange information with each other as well as with systems that provide sensor observations and/or analytical processing. In order to coordinate these interchanges, any system of digital twin systems coordination needs to be based on a common spatial-temporal framework that aligns not only the persistent elements of each twin, but also the sensors and other sources of dynamic information. Issues addressed particularly in OGC Testbeds include API’s for system-to-system interchange of dynamic information (e.g. moving features), services for discovery across distributed systems, and standardization of training data across multiple machine learning models.

Existing OGC API’s do not directly address all of the requirements posed by digital twin interoperability needs. The formulation of OGC API elements as “building blocks”, however, presents the opportunity to assemble existing API building blocks into a more appropriate “Digital Twin API” interface specifically directed at those needs. The specification and prototyping of such an interface would be a valuable contribution to the advancement of urban systems towards the digital twin ideal.

Figure 1. Conceptual Diagram of the network of interfaces and processes connected with Digital Twin Platforms for Smart Built Environments

3. Urban Digital Twin Interoperability Pilot Objectives

The objectives of the Urban Digital Twin Interoperability Pilot are to improve interoperability of geospatial data and analyses within digital twins and lay the foundations for better interoperability between Digital Twins developed for separate applications. In detail it aims to:

  • Develop a Pilot plan to implement digital twin interoperability scenarios and a supporting standard digital twin API for Urban noise analysis and Situational analysis of geo-referenced still and moving imagery for use cases at a Smart City.

  • Prototyping open standard interfaces for:

    • Data collection from the real world to an Urban Digital Twin

    • Data exchanges between UDTIP and analytic processes

    • Presentation of analytic processing results

  • Collaboratively exploring best tools and representations through co-design with scientists, technology developers, and decision-makers to develop, test, and validate advanced interoperability and integration methods for Urban Digital Twins.

3.1. Benefits to the stakeholder community

The outcomes of the UDTIP initiative will benefit not only its sponsors and direct Participants, but the broader stakeholder community through:

  • The creation of a shared forum for technical experts, domain experts, users of geospatial data and systems, and community stakeholders across the diverse applications related to the planning, management, and future development, and living in urban places.

  • Building an integrated source of information on key technologies, standards, and data critical for geospatially-enabled applications of Urban Digital Twins.

  • Providing insights into where the geospatial data and infrastructure needs of Smart Camps and Smart Cities stakeholders intersect and diverge.

  • Making connections between the Smart City and UN Smart Camp communities and the communities engaged in related OGC initiatives to seed future collaborations and create opportunities for new partnerships.

4. Benefits to Participants

This initiative provides an outstanding opportunity to connect with stakeholders across the Urban ecosystem, engage with the latest research on geospatial system design, concept development, and rapid prototyping with organizations (Sponsors & Participants) across the globe. The initiative provides a business opportunity for stakeholders to mutually define, refine, and evolve service interfaces and protocols in the context of hands-on experience and feedback. The OGC Urban Digital Twins Pilot will contribute towards an open, multi-level infrastructure that integrates data, technologies, requirements and objectives from diverse contexts and application domains. It will contribute to the technology and governance stack that enables the integration of data including historical observations, real time sensing data, reanalysis, forecasts and future projections. The Sponsor, the Land and Housing Agency of Korea, are supporting this vision with cost-sharing funds to partially offset the costs associated with development, engineering, and demonstration of these outcomes. This offers selected Participants a unique opportunity to recoup a portion of their initiative expenses. OGC COSI Program Participants benefit from:

  • Access to funded research & development

  • Reduced development costs, risks, and lead-time of new products or solutions

  • Close relationships with potential customers

  • First-to-market competitive advantage on the latest geospatial innovations

  • Influence on the development of global solutions and standards

  • Partnership opportunities within our community of experts

  • Broader market reach via the recognition that OGC standards bring.

5. Master Schedule

The following table details the major Initiative milestones and events for the Urban Digital Twins Interoperability Pilot. Dates are subject to change.

Table 1. Master Schedule
Milestones Project Month Description


3 May 2024

Pilot Call for Participation Opens


14 May 2024

Bidders Webinar


3 June 2024

Pilot Call for Participation Closes


25-26 June 2024

Pilot Kickoff


20 December 2024

Draft Engineering Report


21 February 2025

Final Engineering Report and operating prototype

During the pilot, virtual weekly check-ins will be held for participants to discuss progress, highlight challenges, and share views on key issues. Participants in meetings will contribute to the pilot’s final report by providing quick comments after each meeting, capturing discussion and lessons learned which will complement the technical outcomes included in the report.

6. Participation

6.1. Who can participate

The OGC welcomes proposals to participate in its Initiatives from organizations and individuals active in the development, management, and use of geospatial data, technologies and systems. Proposers may be active in industry, government (national, regional, local), research, non-profit, community, or other sectors. Past participants have included providers of services and platforms, modelers, end users of platforms and data, researchers, and other stakeholders in relevant domains.

You do not need to be a member of the Open Geospatial Consortium to propose to participate. If your organization’s proposal is selected, you or your organization must become an OGC member if not already one. This is to ensure all participants have equal access to the tools and documentation developed and shared throughout the project phase.

6.2. How to participate

The UDTIP is designed to enable interested organizations to participate in a range of ways, from simply engaging in the co-design process without committing any resources other than the participant’s time, to providing funding, in-kind or paid services, or providing a resource such as a dataset or access to infrastructure. Key mechanisms for engagement include:

  • Provide technical expertise Commit staff time to the Pilot to regularly join meetings, develop data and software components, test and evaluate implementations, or produce documentation. Contribute your organization or community’s perspective on how tools should be designed and what would meet your needs as a user by actively participating in workshops and co-design exercises. Add your perspective as a technical or domain expert by providing feedback on the design and implementation of the architecture.

  • Provide a use case Share a real world case study which can be used to inform the development of the UDTIP architecture and demonstrate how it can be used to create more FAIR processes and workflows, leading to better outcomes for users. Sample use cases may be provided when you make your proposal with the expectation that these would be refined in consultation with other UDTIP Pilot team members.

  • Provide data or tools Make an contribution of existing data, platforms, research or other resources (e.g. models, digital infrastructure components) to support the Pilot.

7. Technical Objectives

This section identifies the technical objectives of the UDTIP Initiative and the corresponding activities and deliverables participants make a proposal (bid) to undertake in order to help achieve the Initiative’s aims. These activities and deliverables constitute the major part of each participant’s contribution to the UDTIP Initiative, together with their contribution to Engineering Reports and other materials capturing the process.

It is expected that proposals to achieve these technical objectives will build on and refer to the OGC standards baseline, i.e., the complete set of member-approved Abstract Specifications, Standards including Profiles and Extensions, and Community Practices, where relevant.

Figure 2. Conceptual Diagram of analytical, visualization, and data modules connected through a smart city platform with suggested potential OGC API connection mechanisms.

8. Technical Objectives and Deliverables

  1. TO1:Urban traffic noise modeling to support urban planning and management The capacity to generate predictive noise models based on predicted traffic patterns and/or historic traffic and traffic noise data will enable the use of digital twins for several aspects of urban planning and city management. Relevant aspects include the design and management of road networks, the placement of traffic control mechanisms e.g. lights and detours, and traffic volume by vehicle type e.g. passenger cars and buses and trucks, and road pavement type e.g. aspahalt and concrete, and the planning of locations of buildings and siting of public facilities where noise levels should be considered. Participants working on this deliverable (D100) will produce a design of a prototype API- and OGC standards enabled workflow to enable reusable and reproducible execution of a noise simulation integrating IoT sensor data and 3D built environment models within an Urban Digital Twin. (D100) This deliverable will include documentation of the workflow carried out for the following tasks:

    1. Production of a parametric urban 3D noise model and supporting workflow

      1. The noise model and workflow will incorporate 3D city models, provided by the sponsors, typical of those used in the planning phase of a Smart City

      2. The workflow will include steps for conversion from BIM/CAD to CityGML 2.0

      3. The noise modeling workflow will include the conversion of estimated traffic profiles to synthetic noise data, providing a mechanism for use of traffic profile data as an input. Samples of data will be provided by the sponsors.

      4. The noise modeling workflow will include the direct integration of noise sensor reading data for a set of given points. Synthetic sensor data may be used. Use of the SensorThings API standard is encouraged for this aspect of D100.

    2. Integration of the noise model and 3D city model within a Digital Twin Platform capable of:

      1. Receiving updates to the 3D built environment model

      2. Receiving noise levels and additional data at given points

      3. Communicating with urban noise analysis module

      4. Providing analysis results to the visualization module described in Technical Objective 4 (D104)

      5. Exchanging data and interoperating with the UDT described in Technical Objective 2 (D101/D102) using the mechanism described in Technical Objective 3 (D103)

  2. TO2: Detection and identification of unwanted objects (obstacles and unauthorized dumping) in SmartCity contexts (D101 and D102) The ability to use sensors and cameras to support the management of built-up environments is critical to the ongoing operations of Smart Cities. In the context of cities, it is essential to detect obstacles to mobility. While systems to alert people to the presence of alterations to road vehicle mobility, including the cause, are operational, the detection of unwanted objects acting as obstacles to active transport (walking, jogging, cycling) is not well developed. Equally, the capability to detect unwanted objects, including illegal trash dumps and abandoned objects, is under-developed. The participants on these deliverables will collaborate to develop a prototype system and supporting workflow to:

    1. Enable Camera Imagery Interoperability (D101) for training / testing / validation for ML workflows (D101). The prototype system and workflow must allow Geo-Referenced Camera Images produced by multiple sensor types (those typically used to capture imagery, still or video, from moving vehicles) to be prepared for use in ML feature detection and scene understanding workflows. The multi-source image sets are expected to maintain essential metadata to enable traceability. Essential metadata for this deliverable includes GeoPose 1.0 for camera position and FoV and Trajectories documented following the Moving Features standard.

    2. Enable Geo-AI Analysis Interoperability (D102). Design a prototype API and OGC standards-enabled workflow to enable reusable and reproducible execution of an ML-driven image-based object detection within an Urban Digital Twin. The focus of the ML training should support the overall technical objective. The ML-driven system should, wherever possible, use the input imagery formats and metadata formulations developed by the D101 participants. The training data and metadata outputs should be provided following the TrainDML: TrainingDML for AI standard.

    3. The outputs of D101 and D102 should be interoperable with the Urban Digital Twin described in Technical Objective 1 (D100) using the mechanism described in Technical Objective 3 (D103)

  3. TO3: Inter-module Interoperability to support portability and reuse for diverse UDT applications (D103). Enabling the creation of Urban Digital Twins for a range of specific applications and promoting portability and reuse of their modules requires development of explicit mechanisms for UDT module interoperability, enabled by standards. The participants working on this technical objective will collaborate with those on D100, D101 and D102 to deliver:

    1. Inter-module Interoperability (D103). Design of a prototype for API- and OGC standards enabled data flows between Digital Twin modules built for different applications, using the two applications in this pilot as an exemplar use case.

    2. The participants working on this deliverable are responsible for developing the functionality to coordinate exchange of data, metadata and code as required between the data, analytic, and visualization modules produced for the UDTIP.

    3. Participants working on this deliverable are expected to report on any limits of OGC standards for supporting this application within their Engineering Report contribution. Planning for generalized UDT interoperability beyond the specific use cases in this Pilot is encouraged.

  4. TO4: Communication and Engagement with the community of practice involved in designing, developing, operating, and using urban digital twins is essential to ensuring the outcomes of the Pilot are fit for purpose, well aligned with real user needs, and have a path to uptake. The participants working on this technical objective will collaborate with all other participants to:

    1. Produce a Visualization (D104) of results to convey the value of interoperability to external stakeholders.

    2. Lead Stakeholder Engagement (D105). Active engagement throughout the Pilot process is expected with the Land and Housing Agency of Korea, the UN GSC, and wider stakeholder community outwith the Participant organizations to gather information on their priorities and requirements as users and engage them in evaluation of the prototypes. Communities engaged may include a range of organizations interested in digital technologies for urban planning and management, organizations using urban digital twins, and organizations developing digital twins in other contexts. This engagement could take the form of user needs assessments, paper-based design workshops, prototype reviews, or other activities.

9. Deliverables Summary

  • D001 Engineering Report – Co-editorship of an Engineering Report capturing key results and experiences from this project. The Engineering Report will contain a plain language executive summary to clearly outline the motivations, goals, and critical outcomes of this Initiative. It will include sections on any interoperability gap analysis; usability of data products for specific use cases (e.g. in support of the urban planning); and integration of complementary data (e.g. statistics on human population, building materials attributes). The report will be produced in collaboration with OGC staff.

  • D100 Noise Modeling Interoperability Design of a prototype API and OGC standards enabled workflow to enable reusable and reproducible execution of a noise simulation integrating IoT sensor data and 3D built environment models within an Urban Digital Twin.

  • D101 Camera Imagery Interoperability for training / testing / validation for ML workflows.

  • D102 Geo-AI Analysis Interoperability Design of a prototype API and OGC standards enabled workflow to enable reusable and reproducible execution of a ML-driven image-based object detection within an Urban Digital Twin.

  • D103 Inter-module Interoperability Design of a prototype for API and OGC standards enabled data flows between Digital Twin modules built for different applications, using the two applications in this pilot as an exemplar.

  • D104 Visualization of results to convey the value of interoperability to external stakeholders.

  • D105 Stakeholder Engagement with LH, the UN GSC, and wider stakeholder community outwith the Participant organizations to gather information on their priorities and requirements as users and engage them in evaluation of the prototypes.