# HALOWERK Europe Land – Local Relief (Parcel Polygon)

> HALOWERK Europe Land – Local Relief (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 local relief (difference between maximum and minimum surface elevation) for a caller-supplied polygon parcel across 30 European countries.

## Facts

- Endpoint: POST https://euroland.halowerk.com/v1/europe-local-relief-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-local-relief-parcel-polygon-7ba757a1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_uFTocaX9yZuJ33BnbEe_p

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-local-relief-parcel-polygon-7ba757a1 -d '<json body>'
```

Example prompt: What's the local relief — the difference between the highest and lowest elevation — inside this parcel in northern France? The polygon corners are roughly [2.31, 48.85], [2.33, 48.85], [2.33, 48.87], [2.31, 48.87].

## When to prefer this

Use this endpoint when you need the terrain roughness or elevation variability (local relief) for a specific polygon-defined parcel within Europe, as opposed to a fixed-radius circular buffer or a point lookup. It is ideal for land assessment, agricultural planning, solar/wind site suitability, and real-estate due diligence workflows where the parcel boundary is already known.

## Known failure modes

- Polygon spans more than 0.25 degrees — request rejected with validation error
- Fewer than 3 coordinate pairs supplied — schema validation failure
- Coordinates fall outside covered European extent (lon −31.5 to 40.5, lat 34 to 72.5) — out-of-coverage error
- Malformed coordinate array (wrong nesting or type) — 400 bad request
- Payment not attached or insufficient USDC — 402 payment required

## How this service works

Difference between maximum and minimum sampled surface elevation. The service evaluates the bounded polygon supplied by the caller and returns standardized units across all 30 covered countries.

## Output

A numeric local relief value representing the difference between the maximum and minimum sampled surface elevation within the supplied polygon, expressed in standardized units, covering any of the 30 supported 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-local-relief-parcel-polygon-7ba757a1/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)