# HALOWERK Southern Land – Greece Mean Slope

> HALOWERK Southern Land – Greece Mean Slope is a paid API for AI agents from suedland.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 given coordinate in Greece, validated against the Natural Earth boundary.

## Facts

- Endpoint: POST https://suedland.halowerk.com/v1/gr-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-southern-land-greece-mean-slope-30b84149
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_q8W-46o5K5wfZ4yhr_4gJ

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-southern-land-greece-mean-slope-30b84149 -d '<json body>'
```

Example prompt: What's the mean slope of the terrain at latitude 37.9, longitude 23.7 in Greece? I need it for a land suitability assessment.

## When to prefer this

Choose this endpoint when you need mean terrain slope specifically for a point location within Greece, especially for land suitability, agriculture, construction, or environmental assessments. It is distinct from maximum slope (which uses adjacent-cell max gradient) and provides a smoothed average gradient rather than a peak value.

## Known failure modes

- Coordinate outside Greece boundary — rejected before payment, no charge incurred
- 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 — schema validation error
- Payment failure via x402 — request not processed

## How this service works

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

## Output

A numeric value representing the mean first-order surface gradient (slope) across the analysis grid at the specified coordinate. Coordinates outside the Natural Earth boundary for Greece 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-southern-land-greece-mean-slope-30b84149/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from suedland.halowerk.com](https://www.zero.xyz/host/suedland.halowerk.com/llms.txt)