> For the complete documentation index, see [llms.txt](https://mims.oascities.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mims.oascities.org/local-digital-twins/mim8-local-digital-twins/mechanisms.md).

# Mechanisms

{% hint style="info" %}
These Mechanisms are under active development
{% endhint %}

| M1.: API-based LDT Resource Access                                                                                                                                                                                                                                       |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| R1.1, R1.3, R1.4, R2.1, R2.2, R2.3, R2.5, R2.6                                                                                                                                                                                                                           |
| <p>Use standard APIs and service interfaces, including where relevant:</p><ul><li>OGC API Features;</li><li>OGC API Processes;</li><li>OGC 3D Tiles;</li><li>REST APIs;</li><li>NGSI-LD APIs;</li><li>IoT transmission protocols;</li><li>database connectors.</li></ul> |
| <p>Expose, where relevant:</p><ul><li>datasets;</li><li>transformed data;</li><li>simulation outputs;</li><li>model inputs;</li><li>model services.</li></ul>                                                                                                            |

{% hint style="info" %}
This mechanism should reference MIM0 for data access and MIM7 for geospatial access. The MIM8-specific point is that these resources must be accessible for orchestration inside LDT workflows.
{% endhint %}

| M2: Standardised Data and Output Formats                                                                                                                                                                                                                                                                                                                                                                                                      |
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| R2.2, R3.3, R5.1, R6.1, R6.2, R6.3, R6.4, R6.5, R6.6, R6.7                                                                                                                                                                                                                                                                                                                                                                                    |
| <p>Use standard or widely adopted formats, including where relevant:</p><ul><li>geospatial data: GeoJSON, CityJSON, CityGML, GeoTIFF;</li><li>3D and visualisation data: 3D Tiles, CityJSON, pixel streaming.</li><li>simulation data: NetCDF, HDF5;</li><li>semantic data: RDF, OWL, JSON-LD;</li><li>IoT/context data: NGSI-LD, FIWARE Smart Data Models.</li><li>cloud-optimised formats: COG (Cloud Optimised GeoTIFF), Parquet</li></ul> |

{% hint style="info" %}
**Note**

MIM2 is relevant for representation and semantics, while MIM7 is relevant for geospatial formats, and MIM8 is concerned with whether these formats can support model execution, simulation outputs, and visualisation.
{% endhint %}

| M3: Model-as-a-Service                                                                                                                                                                                                                                                                                              |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| R3.1, R3.2, R3.3, R3.4, R3.6, R3.7                                                                                                                                                                                                                                                                                  |
| <p>Expose deterministic, simulation, AI or analytical models through service interfaces,  including where relevant:</p><ul><li>OGC API Processes;</li><li>REST APIs;</li><li>containerised model services;</li><li>model registries;</li><li>MCP-style tool interfaces for LLM or agentic AI interaction.</li></ul> |
| <p>Enable:</p><ul><li>local or remote model execution;</li><li>reuse of models across workflows, domains or LDTs;</li><li>clear description of required input data;</li><li>clear description of generated outputs;</li><li>versioning and provenance.</li></ul>                                                    |

{% hint style="info" %}
This mechanism is the core of MIM8 by promoting the reuse of models across domains, communities, use cases, and LDTs.
{% endhint %}

| M4: LDT Workflow Orchestration                                                                                                                                                                                                                                                                                                                                                                                           |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| R1.5, R2.4, R3.5, R3.8, R4.1, R4.2, R4.3, R4.4, R4.5, R4.6                                                                                                                                                                                                                                                                                                                                                               |
| <p>Use an orchestration layer or workflow mechanism that can:</p><ul><li>connect data sources to models;</li><li>pass outputs from one step to another;</li><li>validate required inputs before model execution;</li><li>monitor workflow execution; </li><li>record provenance; for instance through Distributed Ledger Technologies (DLTs) or Non-Fungible Tokens (NFT)</li><li>support scenario comparison.</li></ul> |
| <p>Possible implementations include:</p><ul><li>workflow engines;</li><li>LDT orchestration platforms;</li><li>dataflow tools;</li><li>scenario managers;</li><li>controlled agent-based orchestration.</li></ul>                                                                                                                                                                                                        |

| M5: Multi-view Output and Visualisation Access                                                                                                                                                                                                                                      |
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| R5.1, R5.2, R5.3, R5.4                                                                                                                                                                                                                                                              |
| <p>Expose outputs through formats or services that can be consumed by different visualisation tools, including:</p><ul><li>2D maps;</li><li>GIS;</li><li>3D scenes;</li><li>dashboards;</li><li>reports;</li><li>VR/AR environments;</li><li>natural-language interfaces.</li></ul> |
| <p>Use, where relevant:</p><ul><li>OGC 3D Tiles;</li><li>CityJSON;</li><li>GeoJSON;</li><li>raster/vector layers;</li><li>dashboard APIs;</li><li>scenario-output packages.</li></ul>                                                                                               |


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://mims.oascities.org/local-digital-twins/mim8-local-digital-twins/mechanisms.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.