LDT Interoperability Blueprint

1. Introduction

The Interoperability Blueprint provides business, organisational, and technical guidelines for building our own Local Digital Twin (LDT) and interconnecting with other LDTs. An LDT is a digital representation of physical assets, systems, or processes in a defined local context (for example, city, district, building, industry, port, and airport). LDTs are based on structured data models and contextualised data. They leverage either historical data, near real-time data, or real-time data, and they enable visualisation, analysis, simulation, and reasoning services that support decision-making. First, we will elaborate on why LDTs can be useful, followed by a high-level overview of an LDT. Next, we will explain the importance of being able to add new components to an LDT (Section 1.3) and discover existing components that can be added to an LDT (Section 1.4). Finally, we will discuss how this blueprint aligns with Minimum Interoperability Mechanisms (MIMs) Plus (Section 1.5) and how data spaces and LDTs are related (Section 1.6). The remainder of this deliverable is structured as follows:

Chapter 2: The business and organisational building blocks and the technical building blocks.
Chapter 3: The workflows an LDT should support.
Chapter 4: The technical architecture and the business and organisational overview.
Chapter 5: How the business and organisational architecture and technical architecture support the workflows.
Chapter 6: How to build an LDT based on the other chapters.

Although this blueprint mainly guides us through the process of building a new LDT with the focus on interoperability, we can also use its recommendations for updating an existing LDT and interlinking LDTs. The scope of the blueprint isn’t to offer guidelines for every use case in which an LDT is being built or has been built, as every LDT operates in a very specific context.

1.1. Why use an LDT

An LDT is a virtual replica of a territory based on structured data models, real-time data feeds, and potentially 3D representations, which can integrate simulation models (flows, usage, impacts, and so on). It aims to dynamically represent the territory at various spatial and temporal scales to analyse, understand, anticipate, and simulate the effects of public policies, environmental hazards, climate change, development projects or disruptions. The digital twin supports strategic decision-making, consultation, foresight, and scenario design. It can even include automated decision-making and execution. It can incorporate historical datasets, time-delayed data, Building Information Modelling (BIM), Geographic Information Systems (GIS), and/or specific models (mobility, climate, energy, and so on). LDTs can offer the following capabilities to users:

Descriptive: Current (and past) state of the real-world asset - static and dynamic. Bidirectional connection between real-world assets and the LDT.
Predictive: Extends the descriptive capability by providing predictions on the way the real asset could evolve in the future, using predictive models to envision possible futures.
Prospective: Conducts "what-if" analyses to evaluate the potential consequences of actions.
Prescriptive: Extends (or, in extreme cases, executes) the prospective capability with suggested actions on the real system to achieve a given objective based on the analysis.
Diagnostic: Explains situations or alerts about deviations from expected conditions. Capability for evaluating what happened, especially in the case of a malfunction of the real asset.

Note that we do not derive this definition of an LDT from a formal international standard. Instead, it is a project-specific conceptualisation influenced by existing frameworks such as Digital Twins, the EU LDT Toolbox, MIMs Plus 8 on Local Digital Twins, Smart City models, and Data Spaces. While relevant standards (for example, ISO 23247, ISO/IEC 30182, and ISO 30173) provide partial guidance, there is currently no universally accepted standard definition for LDTs in the context of urban or territorial systems.