# HALOWERK Baltic Land – Estonia Terrain Ruggedness (Surface Elevation Std Dev)

> HALOWERK Baltic Land – Estonia Terrain Ruggedness (Surface Elevation Std Dev) is a paid API for AI agents from baltikum.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 at a given coordinate within Estonia, quantifying terrain ruggedness.

## Facts

- Endpoint: POST https://baltikum.halowerk.com/v1/ee-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-baltic-land-estonia-terrain-ruggedness-surface-elevation-std-60ce4933
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tQFFnBCo3osifudirmrMl

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-baltic-land-estonia-terrain-ruggedness-surface-elevation-std-60ce4933 -d '<json body>'
```

Example prompt: What is the terrain ruggedness at latitude 58.95, longitude 25.3 in Estonia — give me the standard deviation of surface elevations there.

## When to prefer this

Choose this endpoint when you need a quantitative measure of terrain roughness or topographic variability (standard deviation of elevations) at a specific point in Estonia. It is ideal for site suitability analysis, infrastructure planning, environmental modeling, or any task requiring a nuanced elevation variability metric rather than just max/min range. For elevation range instead of spread, use the sibling endpoint returning the difference between max and min elevation. For slope or runoff tendency, use the dedicated gradient or runoff siblings.

## Known failure modes

- Coordinate outside Estonia boundary — request rejected without charge
- Latitude or longitude out of European coverage range — validation error
- Malformed coordinate values — input schema validation failure
- Service unavailability — HTTP 5xx error

## How this service works

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

## Output

A numeric value representing the standard deviation of sampled surface elevations at the queried coordinate, indicating the degree of terrain ruggedness. Coordinates outside Estonia's Natural Earth boundary are rejected before 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-baltic-land-estonia-terrain-ruggedness-surface-elevation-std-60ce4933/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from baltikum.halowerk.com](https://www.zero.xyz/host/baltikum.halowerk.com/llms.txt)