# HALOWERK Atlantic Land – Netherlands Maximum Surface Slope

> HALOWERK Atlantic Land – Netherlands Maximum 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 maximum adjacent-cell surface gradient (steepest slope) across the analysis grid for a coordinate within the Netherlands boundary.

## Facts

- Endpoint: POST https://atlantikland.halowerk.com/v1/nl-max-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-netherlands-maximum-surface-slope-a89f3008
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lwXDVc88I3vftsxT5BKDb

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-netherlands-maximum-surface-slope-a89f3008 -d '<json body>'
```

Example prompt: What is the maximum surface slope gradient at latitude 52.37 and longitude 4.89 in the Netherlands — I need the steepest adjacent-cell gradient for a terrain analysis.

## When to prefer this

Use this endpoint when you need the steepest terrain gradient (maximum adjacent-cell slope) specifically for a coordinate within the Netherlands, as opposed to mean slope or other terrain metrics. It is ideal for erosion risk, construction suitability, and runoff modeling workflows where peak gradient matters more than average slope. The built-in Netherlands boundary validation ensures results are geographically meaningful.

## Known failure modes

- Coordinate outside Netherlands Natural Earth boundary — request rejected before payment
- Latitude or longitude outside European coverage range (lat 34–72.5, lon -31.5–40.5) — validation error
- Malformed request body or missing required coordinate fields — schema validation error
- Payment failure via x402 protocol — transaction not completed
- Temporary service unavailability — HTTP 5xx response

## How this service works

Maximum adjacent-cell surface gradient across the analysis grid. The coordinate is validated against the Natural Earth boundary for Netherlands; results outside it are rejected before payment.

## Output

A numeric value representing the maximum adjacent-cell first-order surface gradient (steepest slope) across the analysis grid at the given coordinate, constrained to the Netherlands Natural Earth boundary. Coordinates outside the Netherlands boundary are rejected before processing.

## 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-netherlands-maximum-surface-slope-a89f3008/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)