# HALOWERK Land Compare – Solar Orientation Index (Two Sites)

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

Computes the solar orientation index for exactly two European coordinates and returns the signed difference and the winning location.

## Facts

- Endpoint: POST https://landvergleich.halowerk.com/v1/compare-two-solar-orientation
- 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-land-compare-solar-orientation-index-two-sites-90af9189
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_99nR0T2APagxcCfytJ9Rt

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-two-sites-90af9189 -d '<json body>'
```

Example prompt: Compare the solar orientation index for two plots I'm considering: one at latitude 48.85, longitude 2.35 near Paris, and another at latitude 47.37, longitude 8.54 near Zurich — tell me which one scores higher and by how much.

## When to prefer this

Use this endpoint when you need to compare solar orientation specifically for exactly two European locations and want a single definitive metric with a signed difference and winner. Prefer this over multi-site ranking endpoints when the comparison is binary and precision of the two-site delta is important. Best suited for solar siting, land valuation, agricultural planning, or real estate decisions within Europe.

## Known failure modes

- Coordinates outside European coverage (latitude 34–72.5, longitude -31.5–40.5) will be rejected
- Fewer or more than exactly two location objects in the array returns a validation error
- Missing required latitude or longitude fields causes a schema validation failure
- Identical or very close coordinates may yield a near-zero difference with no clear winner
- Payment failure or insufficient USDC balance results in a 402 response

## How this service works

Measures solar orientation index for exactly two European coordinates with one method and reports the signed difference and winner where meaningful.

## Output

Returns the solar orientation index value for each of the two input European coordinates, along with the signed numerical difference between them (first minus second or clearly labeled), and identifies the winning location where the difference is meaningful.

## 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": 2,
   "minItems": 2
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-land-compare-solar-orientation-index-two-sites-90af9189/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)