# HALOWERK Nordic Land – Surface Ruggedness Index (Sweden)

> HALOWERK Nordic Land – Surface Ruggedness Index (Sweden) is a paid API for AI agents from nordland.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns the standard deviation of sampled surface elevations (terrain ruggedness) for a given WGS84 coordinate validated within Sweden's boundaries.

## Facts

- Endpoint: POST https://nordland.halowerk.com/v1/se-ruggedness
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-nordic-land-surface-ruggedness-index-sweden-c3840b57
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xhDPnnC3GexvFbxuIszTb

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 halowerk-nordic-land-surface-ruggedness-index-sweden-c3840b57 -d '<json body>'
```

Example prompt: What's the terrain ruggedness at latitude 63.2 and longitude 14.5 in Sweden — I need the standard deviation of surface elevations for that point.

## When to prefer this

Choose this endpoint when you need a terrain ruggedness metric (elevation standard deviation) specifically for locations within Sweden. It is pre-validated against Sweden's boundary, so you avoid paying for out-of-bounds queries. Prefer this over generic elevation APIs when you need a ruggedness statistic rather than a raw elevation value, or when working in a Nordic/Scandinavian geospatial context.

## Known failure modes

- Coordinate outside Sweden's Natural Earth boundary — request rejected before payment with a validation error
- Latitude or longitude outside the published European coverage range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Network timeout or service unavailability
- Malformed input (non-numeric or missing coordinates)

## How this service works

Standard deviation of sampled surface elevations. The coordinate is validated against the Natural Earth boundary for Sweden; results outside it are rejected before payment.

## Output

A numeric value representing the standard deviation of sampled surface elevations at the queried coordinate, indicating terrain ruggedness. Coordinates outside Sweden's Natural Earth boundary are rejected before any computation or payment is processed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "latitude": {
   "type": "number",
   "maximum": 72.5,
   "minimum": 34,
   "description": "WGS84 latitude inside the published European coverage."
  },
  "longitude": {
   "type": "number",
   "maximum": 40.5,
   "minimum": -31.5,
   "description": "WGS84 longitude inside the published European coverage."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-nordic-land-surface-ruggedness-index-sweden-c3840b57/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from nordland.halowerk.com](https://www.zero.xyz/host/nordland.halowerk.com/llms.txt)