# HALOWERK Central Land – Austria Mean Surface Slope

> HALOWERK Central Land – Austria Mean Surface Slope is a paid API for AI agents from mitteleuropa.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).

Returns the mean first-order surface gradient (slope) across an analysis grid for a given coordinate within Austria, validated against Natural Earth boundaries.

## Facts

- Endpoint: POST https://mitteleuropa.halowerk.com/v1/at-mean-slope
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-central-land-austria-mean-surface-slope-ef96f416
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LcREPr5-Cc1Qg1HJE-bbG

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-central-land-austria-mean-surface-slope-ef96f416 -d '<json body>'
```

Example prompt: What is the mean surface slope at coordinates 47.8° N, 13.0° E in Austria? I need the average terrain gradient across the analysis grid for that location.

## When to prefer this

Use this endpoint when you specifically need mean surface slope (terrain gradient) for a point within Austria, particularly for land analysis, site suitability, agriculture, construction planning, or environmental assessment. It is preferable over generic DEM APIs when Austrian boundary validation is required before billing and when a concise scalar slope metric suffices rather than a full elevation profile.

## Known failure modes

- Coordinates outside Austria's Natural Earth boundary are rejected before payment is processed
- Coordinates outside the broader European coverage bounds (lat 34–72.5, lon -31.5–40.5) are rejected as invalid
- Malformed or missing latitude/longitude parameters return a validation error
- Coordinates in extreme terrain or data-sparse areas may return null or low-confidence results

## How this service works

Mean first-order surface gradient across the analysis grid. The coordinate is validated against the Natural Earth boundary for Austria; results outside it are rejected before payment.

## Output

A numeric value representing the mean first-order surface gradient (slope) across the analysis grid centered on the provided coordinate. The result quantifies average terrain steepness and is only returned for coordinates validated within Austria's Natural Earth boundary.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "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."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-central-land-austria-mean-surface-slope-ef96f416/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mitteleuropa.halowerk.com](https://www.zero.xyz/host/mitteleuropa.halowerk.com/llms.txt)