# HALOWERK Southern Land – Greece Aspect (Surface Gradient Direction)

> HALOWERK Southern Land – Greece Aspect (Surface Gradient Direction) 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 circular direction of the dominant surface gradient (aspect) in degrees clockwise from north for a given coordinate within Greece.

## Facts

- Endpoint: POST https://suedland.halowerk.com/v1/gr-aspect
- 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-aspect-surface-gradient-direction-15094d04
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jQaGZHrfNdT9QLW342Q8J

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-aspect-surface-gradient-direction-15094d04 -d '<json body>'
```

Example prompt: What direction does the hillside face at latitude 37.98 and longitude 23.73 in Greece — give me the dominant surface gradient direction clockwise from north.

## When to prefer this

Choose this endpoint when you need the slope-facing direction (aspect) specifically for a point in Greece, validated against the Natural Earth boundary. It is purpose-built for Greek terrain and rejects out-of-bounds coordinates before billing, making it safe for automated pipelines. Use it over generic DEM APIs when you need guaranteed geographic constraint and per-call micropayment pricing via x402.

## Known failure modes

- Coordinate outside Greece boundary returns a rejection error (no charge applied)
- Latitude or longitude outside the published WGS84 coverage range returns a validation error
- Invalid or missing coordinate fields return a schema validation error
- Payment failure via x402 protocol prevents the call from completing

## How this service works

Circular direction of the dominant surface gradient, clockwise from north. The coordinate is validated against the Natural Earth boundary for Greece; results outside it are rejected before payment.

## Output

A single numeric value representing the aspect in degrees (0–360, clockwise from north) of the dominant surface gradient at the requested coordinate. Coordinates outside the Greece 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-southern-land-greece-aspect-surface-gradient-direction-15094d04/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)