Usage overview
This section explains how to work with the data layer in LegoCity and how it connects to the dashboard.
It is intended for people who:
- operate or configure context brokers,
- build or maintain update servers that push data into the broker,
- need to understand how data becomes visible as map layers and blocks in the UI.
The Usage section is organised into the following pages.
Data & brokers
Describes the overall data flow and the roles of:
- the context broker, which stores all NGSI-LD entities, and
- update servers, which fetch external data, transform it into entities, and write to the broker.
This page focuses on:
- typical broker setups (single vs multiple brokers),
- how responsibilities are split between broker and update servers,
- why the dashboard reads but does not write to the broker.
Entities
Describes how city information is represented as NGSI-LD entities and how Smart Data Models are used.
This page covers:
- common entity types in a LegoCity deployment,
- how Smart Data Models influence attribute naming and structure,
- conventions for identifiers, types and geospatial attributes,
- guidelines for defining new entity types when requirements change.
API keys & access
Describes how write access to the context broker is controlled.
This page explains:
- how update servers obtain write access,
- patterns for sharing or separating write keys across servers,
- where keys and tokens should be stored,
- basic expectations for key rotation and incident response.
Read access and the role of read-only proxies are also introduced at a high level.
Sample update server
Describes the sample update server included with LegoCity.
This page clarifies:
- the purpose and scope of the sample,
- how it is configured (environment variables, external API, broker access),
- the typical workflow to run it end-to-end,
- how teams can extend it to build their own update servers.
How to use this section
A typical reading order is:
- Data & brokers – to understand the overall data flow.
- Entities – to learn how city concepts are modeled.
- API keys & access – to see how write access is controlled.
- Sample update server – to run a minimal, practical example.
After working through these pages, you should have a clear picture of how data enters the broker and how it is expected to be structured before it is used by the dashboard.