# HALOWERK Europe Land – Terrain Ruggedness (Polygon)

> HALOWERK Europe Land – Terrain Ruggedness (Polygon) is a paid API for AI agents from euroland.halowerk.com, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-15).

Returns the standard deviation of sampled surface elevations within a user-defined polygon, quantifying terrain ruggedness across 30 European countries.

## Facts

- Endpoint: POST https://euroland.halowerk.com/v1/europe-ruggedness-parcel
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-europe-land-terrain-ruggedness-polygon-402595e7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cqf7_R-VozG25oufVCKmW

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-europe-land-terrain-ruggedness-polygon-402595e7 -d '<json body>'
```

Example prompt: Can you calculate the terrain ruggedness for this land parcel in Bavaria? The polygon vertices are roughly [11.5, 47.8], [11.6, 47.8], [11.6, 47.85], [11.5, 47.85] — I want to know how hilly it is before we consider it for a solar installation.

## When to prefer this

Choose this endpoint when you need a polygon-level terrain ruggedness metric for a specific land parcel in Europe, rather than a fixed-radius circular buffer analysis. It is ideal when you have precise parcel boundaries (e.g. cadastral polygons, field boundaries, or project footprints) and need elevation variability as a single standardized index. Prefer it over circular-buffer siblings when the area of interest is irregularly shaped or when parcel geometry fidelity matters.

## Known failure modes

- Polygon spans more than 0.25 degrees — request will be rejected; split into smaller parcels
- Fewer than 3 coordinate pairs provided — invalid polygon geometry error
- Coordinates outside supported European bounding box (lon -31.5 to 40.5, lat 34 to 72.5) — out-of-coverage error
- Polygon self-intersects or is malformed — geometry validation failure
- Payment not provided or insufficient USDC — x402 payment required response

## How this service works

Standard deviation of sampled surface elevations. The service evaluates the bounded polygon supplied by the caller and returns standardized units across all 30 covered countries.

## Output

A numeric value representing the standard deviation of surface elevations sampled within the supplied polygon, expressed in standardized units. This single ruggedness metric quantifies how variable (rough, hilly, or flat) the terrain is within the parcel, covering any location across 30 European countries.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "polygon": {
   "type": "array",
   "items": {
    "type": "array",
    "items": [
     {
      "type": "number",
      "maximum": 40.5,
      "minimum": -31.5
     },
     {
      "type": "number",
      "maximum": 72.5,
      "minimum": 34
     }
    ],
    "maxItems": 2,
    "minItems": 2,
    "additionalItems": false
   },
   "maxItems": 100,
   "minItems": 3,
   "description": "WGS84 polygon ring. The closing coordinate is optional; maximum span is 0.25 degrees."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-europe-land-terrain-ruggedness-polygon-402595e7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from euroland.halowerk.com](https://www.zero.xyz/host/euroland.halowerk.com/llms.txt)