# HALOWERK Atlantic Land – Luxembourg Mean Surface Slope

> HALOWERK Atlantic Land – Luxembourg Mean Surface Slope is a paid API for AI agents from atlantikland.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns the mean first-order surface gradient (slope) across the analysis grid for a given coordinate within Luxembourg's boundary.

## Facts

- Endpoint: POST https://atlantikland.halowerk.com/v1/lu-mean-slope
- 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-atlantic-land-luxembourg-mean-surface-slope-5bb95674
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FP5JK4peccpQJ3zkYCejq

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-atlantic-land-luxembourg-mean-surface-slope-5bb95674 -d '<json body>'
```

Example prompt: What's the mean surface slope at coordinates 49.6116° N, 6.1319° E in Luxembourg? I need the first-order terrain gradient for that location.

## When to prefer this

Choose this endpoint when you specifically need mean surface slope data for a point coordinate within Luxembourg. It is purpose-built for Luxembourg territory analysis with boundary validation before billing, making it cost-safe for exploratory calls. Prefer it over generic elevation or DEM APIs when you need a pre-aggregated gradient value rather than raw elevation, and when your use case is scoped to Luxembourg.

## Known failure modes

- Coordinate outside Luxembourg's Natural Earth boundary — request rejected before payment, returns boundary validation error
- Latitude or longitude outside the published European coverage range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Malformed request body or missing required fields — returns input validation error
- Service unavailable or timeout — returns server error

## How this service works

Mean first-order surface gradient across the analysis grid. The coordinate is validated against the Natural Earth boundary for Luxembourg; results outside it are rejected before payment.

## Output

Returns the mean first-order surface gradient (slope value) computed across the analysis grid for the submitted coordinate, applicable only to points within Luxembourg's Natural Earth boundary. Coordinates outside this boundary are rejected before any 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-atlantic-land-luxembourg-mean-surface-slope-5bb95674/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from atlantikland.halowerk.com](https://www.zero.xyz/host/atlantikland.halowerk.com/llms.txt)