# HALOWERK Land Compare – Solar Orientation Index Ranker (2–10 Sites)

> HALOWERK Land Compare – Solar Orientation Index Ranker (2–10 Sites) is a paid API for AI agents from landvergleich.halowerk.com, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-13).

Measures the solar orientation index for two to ten named European sites and returns a ranked list with ties preserved.

## Facts

- Endpoint: POST https://landvergleich.halowerk.com/v1/rank-sites-solar-orientation
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-land-compare-solar-orientation-index-ranker-2-10-sites-77392808
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_I9ji3j98Ami-sDXHvDPaZ

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-land-compare-solar-orientation-index-ranker-2-10-sites-77392808 -d '<json body>'
```

Example prompt: Rank these four European sites by their solar orientation index — Madrid (40.4168° N, 3.7038° W), Rome (41.9028° N, 12.4964° E), Lisbon (38.7169° N, 9.1399° W), and Athens (37.9838° N, 23.7275° E) — and tell me which has the best solar orientation.

## When to prefer this

Choose this endpoint when you need to compare solar orientation across multiple (2–10) European sites simultaneously and require a ranked output rather than a pairwise signed difference. It is ideal for multi-site selection workflows such as solar farm siting, agricultural planning, or real estate due diligence where knowing relative rank across all candidates matters. For exactly two sites where only the signed difference is needed, a sibling pairwise endpoint may be more appropriate.

## Known failure modes

- Fewer than 2 or more than 10 locations provided — validation error
- Coordinates fall outside European coverage bounds (lat 34–72.5, lon −31.5–40.5) — out-of-coverage error
- Missing required latitude or longitude for a site — schema validation error
- Site name exceeds 60 characters — validation error
- Network timeout or upstream computation failure — 5xx error

## How this service works

Measures solar orientation index for two to ten named European sites and ranks the observed values with ties preserved.

## Output

Returns each named site with its computed solar orientation index value and an ordinal rank (1 = best solar orientation), with ties preserved so equal-scoring sites share the same rank position.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "locations": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "longitude",
     "latitude"
    ],
    "properties": {
     "name": {
      "type": "string",
      "maxLength": 60,
      "minLength": 1
     },
     "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."
     }
    },
    "additionalProperties": false
   },
   "maxItems": 10,
   "minItems": 2
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-land-compare-solar-orientation-index-ranker-2-10-sites-77392808/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from landvergleich.halowerk.com](https://www.zero.xyz/host/landvergleich.halowerk.com/llms.txt)