# HALOWERK Eastern Land – Romania Mean Slope

> HALOWERK Eastern Land – Romania Mean Slope is a paid API for AI agents from ostland.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns the mean first-order surface gradient (slope) across an analysis grid cell for a given coordinate within Romania.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/ro-mean-slope
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-eastern-land-romania-mean-slope-58f94e5d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iDACT7T7cbjYblKrxoN9V

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-eastern-land-romania-mean-slope-58f94e5d -d '<json body>'
```

Example prompt: What's the mean terrain slope at latitude 45.73, longitude 24.15 in Romania? I need the average surface gradient for that location.

## When to prefer this

Use this endpoint when you need mean terrain slope specifically for locations within Romania and require boundary-validated, pay-per-call geospatial data. Prefer it over generic elevation APIs when you need the average first-order gradient (not max or directional slope) and when Romania-specific validation is important for data quality assurance.

## Known failure modes

- Coordinate outside Romania boundary – request rejected with a geographic validation error before payment
- Coordinate within European coverage range but outside Romania – rejected by Natural Earth boundary check
- Missing or malformed latitude/longitude – returns a schema validation error
- Coordinate at edge of coverage grid with insufficient surrounding data – may return null or an error

## How this service works

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

## Output

A numeric value representing the mean first-order surface gradient (slope) across the analysis grid cell covering the requested Romanian coordinate. Coordinates outside Romania's Natural Earth boundary are rejected before any charge is applied.

## 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-eastern-land-romania-mean-slope-58f94e5d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ostland.halowerk.com](https://www.zero.xyz/host/ostland.halowerk.com/llms.txt)