# HALOWERK Nordic Land – Finland Mean Surface Slope

> HALOWERK Nordic Land – Finland Mean 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 2026-09-13).

Returns the mean first-order surface gradient (slope) across an analysis grid for a coordinate point validated to fall within Finland's boundaries.

## Facts

- Endpoint: POST https://nordland.halowerk.com/v1/fi-mean-slope
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-nordic-land-finland-mean-surface-slope-81dc17b5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lSNS7OcwuNugm_Q63C_FH

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-finland-mean-surface-slope-81dc17b5 -d '<json body>'
```

Example prompt: What's the mean surface slope at latitude 61.5 and longitude 25.7 in Finland? I need the first-order gradient for that location.

## When to prefer this

Choose this endpoint when you need a single numeric mean slope value for a specific point in Finland, derived from a surface elevation grid. It is ideal for geospatial analysis workflows, land assessment tools, or environmental screening pipelines that require per-point topographic steepness values specifically within Finland. Prefer it over generic elevation APIs when you need a gradient/slope metric rather than raw elevation, and when Finland-specific boundary validation is required to ensure data quality.

## Known failure modes

- Coordinate outside Finland's Natural Earth boundary — request rejected, no charge applied
- Coordinate within European coverage bounds but outside Finland — boundary validation failure
- Latitude or longitude outside published European coverage range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Payment failure via x402 protocol — call not executed
- No terrain data available for the specific grid cell — null or error response

## How this service works

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

## Output

A numeric value representing the mean first-order surface slope (gradient) across the analysis grid centered on the provided coordinate. The coordinate is pre-validated against Finland's Natural Earth boundary; requests outside Finland are rejected before any charge is incurred.

## 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-finland-mean-surface-slope-81dc17b5/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)