# HALOWERK Atlantic Land – Belgium Mean Surface Slope

> HALOWERK Atlantic Land – Belgium 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 an analysis grid for a coordinate within Belgium

## Facts

- Endpoint: POST https://atlantikland.halowerk.com/v1/be-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-belgium-mean-surface-slope-74c0c226
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wkgWuksCLXXAvTKnZMN3I

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-belgium-mean-surface-slope-74c0c226 -d '<json body>'
```

Example prompt: What's the mean terrain slope at latitude 50.85 and longitude 4.35 in Belgium? I need the first-order surface gradient for that location.

## When to prefer this

Choose this endpoint when you need a precise, pre-validated mean surface gradient specifically for a coordinate within Belgium. It is ideal for geospatial analysis pipelines requiring per-point terrain steepness data without building your own DEM processing stack. Prefer it over general elevation APIs when you need slope (gradient) rather than raw elevation, and when your use case is strictly Belgium-scoped (the built-in boundary validation saves you from billing errors on out-of-bounds queries).

## Known failure modes

- Coordinate outside Belgium's Natural Earth boundary — rejected before payment with a validation error
- Latitude or longitude outside the European coverage range (lat 34–72.5, lon -31.5–40.5) — schema validation failure
- Malformed or missing latitude/longitude fields — request rejected with input schema error
- Network timeout or service unavailability — HTTP 5xx error returned

## How this service works

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

## Output

Returns the mean first-order surface gradient (slope) value across the analysis grid centered on the provided coordinate. The result reflects terrain steepness derived from a digital elevation model. Coordinates outside Belgium's Natural Earth boundary are rejected before any charge is applied.

## 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-belgium-mean-surface-slope-74c0c226/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)