# HALOWERK Land Compare – Topsoil Organic Carbon Comparison

> HALOWERK Land Compare – Topsoil Organic Carbon Comparison 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).

Measures and compares topsoil organic carbon content at exactly two European coordinates, returning the signed difference and identifying which location has higher organic carbon.

## Facts

- Endpoint: POST https://landvergleich.halowerk.com/v1/compare-two-soil-organic-carbon
- 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-topsoil-organic-carbon-comparison-acff36a6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6HiQnNhjcteFDsL3K4ipf

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-topsoil-organic-carbon-comparison-acff36a6 -d '<json body>'
```

Example prompt: Compare the topsoil organic carbon between my two farm parcels — the first is near Bordeaux at longitude 0.42, latitude 44.85, and the second is near Lyon at longitude 4.83, latitude 45.74 — and tell me which one has higher organic carbon and by how much.

## When to prefer this

Use this endpoint when you need a direct, point-in-time comparison of topsoil organic carbon between exactly two European locations. It is purpose-built for pairwise land comparison with a single consistent measurement method, making results directly comparable. Prefer this over general soil data APIs when you specifically need the signed difference and a clear winner between two sites, and when both coordinates fall within European coverage bounds.

## Known failure modes

- Coordinates outside the European coverage area (latitude 34–72.5, longitude -31.5–40.5) will result in an error
- Fewer or more than exactly two locations provided will be rejected
- Missing required latitude or longitude fields cause validation failure
- Locations with no available soil data in the underlying dataset may return null or incomplete values
- Network timeout or upstream data provider unavailability

## How this service works

Measures topsoil organic carbon for exactly two European coordinates with one method and reports the signed difference and winner where meaningful.

## Output

Returns measured topsoil organic carbon values for both input European coordinates, the signed numerical difference between them, and an indication of which location has higher organic carbon content 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-topsoil-organic-carbon-comparison-acff36a6/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)