# HALOWERK SI Solar Orientation Index

> HALOWERK SI Solar Orientation Index is a paid API for AI agents from mitteleuropa.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Computes a south-facing slope orientation index for a given coordinate in Slovenia, derived from terrain aspect and slope using Copernicus DEM data.

## Facts

- Endpoint: POST https://mitteleuropa.halowerk.com/v1/si-solar-orientation
- 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-si-solar-orientation-index-1121d19e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qDwfd00ao_zeNSOi_Vn19

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-si-solar-orientation-index-1121d19e -d '<json body>'
```

Example prompt: What's the south-facing solar orientation index for the location at latitude 46.05 and longitude 14.51 in Slovenia? I want to know how suitable the slope aspect is for solar exposure.

## When to prefer this

Choose this endpoint when you need a fast, precomputed south-facing solar orientation index specifically for locations within Slovenia, and you want aspect-slope composite scoring without running your own DEM analysis. Prefer this over generic elevation APIs when the use case is solar suitability, photovoltaic site selection, or agricultural sun exposure assessment for Slovenian terrain.

## Known failure modes

- Coordinate outside Slovenia boundary rejected before processing (validated against Natural Earth boundary)
- Coordinate outside European coverage range (lat 34–72.5, lon -31.5–40.5) returns validation error
- Malformed or missing latitude/longitude fields return schema validation error
- Payment failure or insufficient USDC balance blocks request

## How this service works

South-facing slope orientation index derived from aspect and slope. The coordinate is validated against the Natural Earth boundary for Slovenia; results outside it are rejected before payment.

## Output

Returns a numeric south-facing slope orientation index derived from combining terrain aspect (compass direction of slope) and slope steepness, using Copernicus DEM GLO-30 data. Higher values indicate stronger south-facing orientation, correlating with greater direct solar irradiance potential. Coordinates outside Slovenia are rejected prior to 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-si-solar-orientation-index-1121d19e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mitteleuropa.halowerk.com](https://www.zero.xyz/host/mitteleuropa.halowerk.com/llms.txt)