# HALOWERK Nordic Land – Iceland Maximum Surface Slope

> HALOWERK Nordic Land – Iceland Maximum Surface Slope is a paid API for AI agents from nordland.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 given coordinate within Iceland.

## Facts

- Endpoint: POST https://nordland.halowerk.com/v1/is-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-nordic-land-iceland-maximum-surface-slope-de3ec122
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kdD-fsnzZFNmGMn55Pa3J

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-nordic-land-iceland-maximum-surface-slope-de3ec122 -d '<json body>'
```

Example prompt: What's the maximum surface slope at latitude 64.13, longitude -21.90 in Iceland? I need the steepest adjacent-cell gradient for that location.

## When to prefer this

Choose this endpoint when you specifically need the maximum steepness (steepest adjacent-cell gradient) for a location in Iceland, such as for terrain hazard assessments, construction feasibility, erosion modeling, or renewable energy siting. It is Iceland-specific and validates coordinates against the Natural Earth boundary before charging, making it suitable for automated pipelines. Prefer it over general DEM APIs when you need a pre-computed, pay-per-call max slope value without managing raw elevation rasters.

## Known failure modes

- Coordinate outside Iceland boundary: request rejected before payment with a boundary validation error
- Latitude or longitude out of the published European coverage range (lat 34–72.5, lon -31.5–40.5): validation error
- Malformed or missing coordinate fields: input schema validation error
- Payment failure: x402 payment not completed, request not processed
- Server-side data gap for sparse coverage areas: may return null or error for unmapped grid cells

## How this service works

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

## Output

A numeric value representing the maximum adjacent-cell surface gradient (steepest slope) across the analysis grid centered on the requested coordinate. Coordinates outside the Iceland 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-nordic-land-iceland-maximum-surface-slope-de3ec122/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from nordland.halowerk.com](https://www.zero.xyz/host/nordland.halowerk.com/llms.txt)