# HALOWERK Europe Land – Aspect (Parcel Polygon)

> HALOWERK Europe Land – Aspect (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 dominant surface aspect (circular direction of steepest downhill gradient, clockwise from north) for a user-supplied WGS84 polygon parcel across 30 European countries.

## Facts

- Endpoint: POST https://euroland.halowerk.com/v1/europe-aspect-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-aspect-parcel-polygon-e8133cbd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rXy1TzKvRJnZHbH5srzx1

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-aspect-parcel-polygon-e8133cbd -d '<json body>'
```

Example prompt: What direction does the dominant slope face on this parcel – it's a polygon with vertices at roughly [8.2, 47.5], [8.25, 47.5], [8.25, 47.48], [8.2, 47.48] in Switzerland? I need the aspect in degrees clockwise from north.

## When to prefer this

Choose this endpoint when you need terrain aspect (slope-facing direction) for a specific bounded land parcel in Europe and require a consistent, standardized output across 30 countries. Prefer it over general GIS APIs when you need parcel-level polygon input rather than a point query, and when you want a ready-to-use numeric bearing rather than raw DEM data you must process yourself. Especially useful for agricultural, solar energy, viticulture, environmental, and real estate workflows that need terrain orientation as an input feature.

## Known failure modes

- Polygon outside covered European extent (coordinates outside lat 34–72.5°N, lon -31.5–40.5°E) returns an error or empty result
- Polygon with fewer than 3 vertices rejected as invalid
- Polygon spanning more than 0.25 degrees in any direction returns a validation error
- Malformed coordinate array (wrong nesting, non-numeric values) returns a schema error
- Payment/authorization failure via x402 protocol results in 402 response with no data
- Very flat terrain may return low-confidence or uniform aspect values

## How this service works

Circular direction of the dominant surface gradient, clockwise from north. The service evaluates the bounded polygon supplied by the caller and returns standardized units across all 30 covered countries.

## Output

A standardized numeric value representing the dominant surface aspect of the supplied polygon, expressed as degrees clockwise from north (0–360°), consistent across all 30 covered European countries. The response reflects the prevailing gradient direction averaged or derived over the parcel area.

## 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-aspect-parcel-polygon-e8133cbd/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)