# HALOWERK Europe Land – Soil Clay Fraction (Parcel Polygon)

> HALOWERK Europe Land – Soil Clay Fraction (Parcel 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 the mean SoilGrids clay fraction (0–5 cm depth) for a user-supplied WGS84 polygon parcel across 30 European countries.

## Facts

- Endpoint: POST https://euroland.halowerk.com/v1/europe-soil-clay-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-soil-clay-fraction-parcel-polygon-63ec9903
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FrL-Im8_ZZhEXj9wcSDwG

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-soil-clay-fraction-parcel-polygon-63ec9903 -d '<json body>'
```

Example prompt: What's the mean topsoil clay fraction for my field in the Netherlands? The parcel corners are at roughly [4.85, 52.30], [4.86, 52.30], [4.86, 52.31], [4.85, 52.31] — I need the 0–5 cm SoilGrids clay value.

## When to prefer this

Choose this endpoint when you need parcel-level (polygon-bounded) mean clay fraction data for the 0–5 cm topsoil layer within the 30 European countries covered by HALOWERK. It is ideal when precise parcel boundaries are known and standardized SoilGrids-sourced clay values are required. Prefer this over point-based lookups when the spatial aggregation across a field or plot boundary matters for decisions like crop planning, land valuation, or environmental modelling.

## Known failure modes

- Polygon spans more than 0.25 degrees — request rejected with validation error
- Fewer than 3 coordinate pairs supplied — invalid polygon error
- Coordinates fall outside the 30-country European coverage area — out-of-bounds error
- Polygon self-intersects or is malformed — geometry error
- Payment not included or insufficient — HTTP 402 payment required

## How this service works

Mean SoilGrids clay fraction for the 0-5 cm layer. The service evaluates the bounded polygon supplied by the caller and returns standardized units across all 30 covered countries.

## Output

A numeric value representing the mean clay fraction (standardized units) in the 0–5 cm soil layer for the supplied polygon, derived from ISRIC SoilGrids, covering 30 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-soil-clay-fraction-parcel-polygon-63ec9903/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)