# HALOWERK Eastern Land – Croatia Terrain Ruggedness (Standard Deviation)

> HALOWERK Eastern Land – Croatia Terrain Ruggedness (Standard Deviation) is a paid API for AI agents from ostland.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 for a given coordinate within Croatia, quantifying terrain ruggedness at that location.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/hr-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-eastern-land-croatia-terrain-ruggedness-standard-deviation-9d4c72be
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VCqz8vQWjrYhaXTVpTWNq

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-eastern-land-croatia-terrain-ruggedness-standard-deviation-9d4c72be -d '<json body>'
```

Example prompt: What's the terrain ruggedness score — specifically the standard deviation of surface elevations — for the coordinates 45.3°N, 16.1°E in Croatia?

## When to prefer this

Choose this endpoint when you need a single numeric terrain ruggedness metric (elevation standard deviation) for a specific point in Croatia. It is particularly useful when you need to distinguish between flat and hilly terrain for site suitability, infrastructure planning, ecological modeling, or recreational route assessment within Croatia. Prefer sibling endpoints for other terrain metrics like mean slope, elevation range, or soil properties.

## Known failure modes

- Coordinate outside Croatia boundary: request rejected before computation with a validation error
- Latitude or longitude out of published European coverage range (lat 34–72.5, lon -31.5–40.5): rejected by schema validation
- Malformed or missing latitude/longitude parameters: schema validation error
- Payment failure (x402): request not processed if USDC payment cannot be confirmed
- Server-side elevation data unavailable for the sampled area: may return an error or null result

## How this service works

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

## Output

A numeric value representing the standard deviation of sampled surface elevations at the specified coordinate, indicating how variable (rugged) the terrain is. The coordinate is first validated against the Natural Earth boundary for Croatia and rejected if outside it. Higher values indicate more rugged, variable terrain; lower values indicate flatter surfaces.

## 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-eastern-land-croatia-terrain-ruggedness-standard-deviation-9d4c72be/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ostland.halowerk.com](https://www.zero.xyz/host/ostland.halowerk.com/llms.txt)