# HALOWERK Europe Land – Solar Orientation Index (Polygon)

> HALOWERK Europe Land – Solar Orientation Index (Polygon) is a paid API for AI agents from euroland.halowerk.com, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-15).

Returns a south-facing slope orientation index derived from aspect and slope for a user-supplied WGS84 polygon within Europe.

## Facts

- Endpoint: POST https://euroland.halowerk.com/v1/europe-solar-orientation-parcel
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-europe-land-solar-orientation-index-polygon-a29d899a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EqQpw4FR7UdJCSZ4SXnoK

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-europe-land-solar-orientation-index-polygon-a29d899a -d '<json body>'
```

Example prompt: Can you calculate the south-facing solar orientation index for this parcel in France? The polygon vertices are: [2.31,48.87], [2.32,48.87], [2.32,48.88], [2.31,48.88].

## When to prefer this

Use this endpoint when you need a standardized solar orientation metric for an arbitrary polygon parcel boundary rather than a fixed circular buffer. It is ideal for actual land parcel shapes (cadastral boundaries, field outlines) and when precise polygon geometry matters for solar suitability analysis across any of 30 European countries.

## Known failure modes

- Polygon has fewer than 3 coordinate pairs — returns validation error
- Coordinates fall outside the European coverage area (longitude outside -31.5–40.5 or latitude outside 34–72.5) — returns out-of-bounds error
- Polygon span exceeds 0.25 degrees — returns size limit error
- Polygon has more than 100 vertices — returns validation error
- Malformed coordinate arrays — returns schema validation error

## How this service works

South-facing slope orientation index derived from aspect and slope. The service evaluates the bounded polygon supplied by the caller and returns standardized units across all 30 covered countries.

## Output

A standardized south-facing slope orientation index value for the submitted polygon, derived from aspect and slope data, consistent across all 30 covered European countries.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "polygon": {
   "type": "array",
   "items": {
    "type": "array",
    "items": [
     {
      "type": "number",
      "maximum": 40.5,
      "minimum": -31.5
     },
     {
      "type": "number",
      "maximum": 72.5,
      "minimum": 34
     }
    ],
    "maxItems": 2,
    "minItems": 2,
    "additionalItems": false
   },
   "maxItems": 100,
   "minItems": 3,
   "description": "WGS84 polygon ring. The closing coordinate is optional; maximum span is 0.25 degrees."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-europe-land-solar-orientation-index-polygon-a29d899a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from euroland.halowerk.com](https://www.zero.xyz/host/euroland.halowerk.com/llms.txt)