# What is on the river

> The Thames is a working waterway, and it broadcasts.

- Category: Transport
- Cadence: live
- Status: Live: values change continuously; cite the retrieval time.
- Dataset key: `live-ships`
- Source: [AISStream](https://aisstream.io/)
- Licence: AISStream terms of use
- Canonical page: [https://londongraph.com/g/whats-on-the-river](https://londongraph.com/g/whats-on-the-river)
- Machine-readable record: [https://londongraph.com/data/whats-on-the-river](https://londongraph.com/data/whats-on-the-river)

## Methodology

AIS transmissions heard over Greater London, via AISStream. Unlike every other feed here this one is a broadcast rather than a request: vessels transmit when they choose to, so there is no endpoint that answers what is on the river now — the server has to have been listening. It holds one socket open and accumulates what it hears, forgetting a vessel after twenty minutes of silence. Carrying AIS is mandatory for larger commercial craft and optional for small ones, so this is what the river is broadcasting rather than a census of what is on it. The count climbs for the first several minutes after a deploy while the table fills.

## Visualisations

- [Map](https://londongraph.com/g/whats-on-the-river): The Thames is a working waterway, and it broadcasts.
- [Vessel types](https://londongraph.com/g/whats-on-the-river?view=vessel-types): Show the mix of vessel classes currently broadcasting.
- [Speed](https://londongraph.com/g/whats-on-the-river?view=speed): Show the distribution of reported vessel speeds.

## Citation guidance

Attribute the original publisher named above and identify LondonGraph as the visualisation and methodology layer. Do not describe live values as a historical census, and do not present placeholder values as observations.