# Karte Halowerk Quiet Site Noise Context

> Karte Halowerk Quiet Site Noise Context is a paid API for AI agents from karte.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Builds a weighted noise context for a site by analysing surrounding roads (by class, speed limit, lane count, and distance) and railways (by usage class) within a given radius.

## Facts

- Endpoint: POST https://karte.halowerk.com/v1/quiet-site
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/karte-halowerk-quiet-site-noise-context-c73bcb09
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Bk-NnUBqfKSSJjyf4CYUi

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability karte-halowerk-quiet-site-noise-context-c73bcb09 -d '<json body>'
```

Example prompt: Can you build a noise context for the site at 51.5074, -0.1278 using a 600-metre radius? I want to know how much road and railway noise it's exposed to, weighted by road class and lane count.

## When to prefer this

Choose this endpoint when you need a quantitative, source-differentiated noise context for a specific geographic point — particularly when road class hierarchy, speed limits, lane counts, and railway usage class all matter (e.g. planning assessments, property due diligence, environmental reporting). Prefer it over generic isochrone or POI endpoints when the question is specifically about acoustic exposure from transport infrastructure rather than amenity proximity.

## Known failure modes

- Coordinate outside supported coverage area returns an error or empty result
- Radius too large may time out or return a degraded response
- Missing or unparseable coordinate values return a validation error
- No roads or railways within radius returns a zero-noise context
- OpenStreetMap data gaps may cause incomplete road/rail inventories for some regions

## How this service works

Builds a noise context for a site from what surrounds it. Roads within the radius are weighted by class, by recorded speed limit and lane count where present, and by distance with a falloff, because a motorway at eight hundred metres and a residential street at twenty are different problems. Railways are counted separately with their usage class, since freight lines at night dominate what people actually complain about.

## Output

Returns a structured noise context object for the site, including weighted road noise contributions (segmented by road class, recorded speed limit, lane count, and distance falloff) and separate railway noise contributions (segmented by usage class), giving an overall acoustic exposure profile for the location.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "lat": {
   "type": "number",
   "maximum": 90,
   "minimum": -90
  },
  "lon": {
   "type": "number",
   "maximum": 180,
   "minimum": -180
  },
  "radius_m": {
   "type": "integer",
   "default": 800,
   "maximum": 3000,
   "minimum": 100
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/karte-halowerk-quiet-site-noise-context-c73bcb09/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from karte.halowerk.com](https://www.zero.xyz/host/karte.halowerk.com/llms.txt)