# HALOWERK Land Compare – Topsoil Nitrogen Two-Point Comparison

> HALOWERK Land Compare – Topsoil Nitrogen Two-Point 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 topsoil nitrogen for exactly two European coordinates and returns the signed difference, absolute values, and a winner designation.

## Facts

- Endpoint: POST https://landvergleich.halowerk.com/v1/compare-two-soil-nitrogen
- 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-nitrogen-two-point-comparison-dabd1abf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-qYlbs5j6qbZfVIcAIHL5

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-nitrogen-two-point-comparison-dabd1abf -d '<json body>'
```

Example prompt: Compare the topsoil nitrogen levels between my two candidate farm plots — one near Paris at latitude 48.85, longitude 2.35 and one near Warsaw at latitude 52.23, longitude 21.01 — and tell me which has higher nitrogen and by how much.

## When to prefer this

Use this endpoint when you need a direct, point-to-point topsoil nitrogen comparison for exactly two European locations. It is purpose-built for binary land comparisons with a signed difference and explicit winner — ideal for agricultural site selection, land due diligence, or ecological suitability assessments within Europe. Choose sibling endpoints for other soil metrics (CEC, texture, built-up share) or for ranking more than two sites.

## Known failure modes

- Coordinates outside European coverage bounds (lat 34–72.5, lon -31.5–40.5) return validation error
- Fewer or more than exactly two locations in the array returns a schema validation error
- Invalid or non-numeric coordinate values cause a 400-level error
- Coordinates in ocean or non-soil areas may return null or no-data responses
- Service unavailability may return 5xx errors

## How this service works

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

## Output

Returns topsoil nitrogen measurements for both input coordinates, the signed numeric difference between them, and a designation of which location has the higher nitrogen value (the 'winner') where 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-nitrogen-two-point-comparison-dabd1abf/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)