# HALOWERK Land Compare – Maximum Slope Comparison

> HALOWERK Land Compare – Maximum Slope 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 maximum terrain slope at exactly two European coordinates, returning the signed difference and identifying the steeper location.

## Facts

- Endpoint: POST https://landvergleich.halowerk.com/v1/compare-two-max-slope
- 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-maximum-slope-comparison-ee139541
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LdLnHP98SdJ7MtyFc8QYL

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-maximum-slope-comparison-ee139541 -d '<json body>'
```

Example prompt: Compare the maximum terrain slope between these two locations in Europe: one at latitude 47.5, longitude 11.2 (named 'Bavaria Alps') and one at latitude 48.8, longitude 2.3 (named 'Paris'), and tell me which site is steeper and by how much.

## When to prefer this

Use this endpoint when you need a direct pairwise comparison of maximum terrain slope between exactly two European locations, with a clear signed difference and winner — rather than ranking multiple sites or retrieving raw slope data without comparison. Prefer this over generic elevation APIs when you specifically need slope steepness (not just altitude) and want a structured comparative result for European coordinates.

## Known failure modes

- Coordinates outside European coverage bounds (lat 34–72.5, lon -31.5–40.5) return a coverage error
- Fewer or more than exactly two locations in the input array returns a validation error
- Malformed coordinate values (non-numeric, out-of-range) return a schema validation error
- Payment failure or insufficient funds returns a 402 Payment Required error
- Unavailable elevation/slope data for a specific coordinate may return a data gap error

## How this service works

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

## Output

Returns the maximum slope value measured at each of the two input coordinates, the signed numerical difference between them, and indicates which location has the steeper slope (the 'winner') 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-maximum-slope-comparison-ee139541/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)