# HALOWERK Eastern Land – Croatia Local Relief

> HALOWERK Eastern Land – Croatia Local Relief 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 local relief (max minus min sampled surface elevation) for a given coordinate within Croatia's boundaries

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/hr-local-relief
- 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-croatia-local-relief-c8788a61
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wJKpzOhnzbUSRw1Goq1o-

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-croatia-local-relief-c8788a61 -d '<json body>'
```

Example prompt: What is the local relief — the difference between the highest and lowest surface elevations — at latitude 45.815 and longitude 15.982 in Croatia?

## When to prefer this

Use this endpoint when you need local terrain relief specifically for points within Croatia and want a cost-effective per-call computation. It is preferable over general DEM APIs when you need boundary-validated results for Croatian coordinates and are operating in an agentic, pay-per-call workflow via x402.

## Known failure modes

- Coordinate outside Croatia's Natural Earth boundary — request rejected before payment
- Latitude or longitude outside the European coverage range (lat 34–72.5, lon -31.5–40.5) — validation error
- Missing required latitude or longitude parameter — schema validation error
- Network or payment processing failure via x402 protocol

## How this service works

Difference between maximum and minimum sampled surface elevation. The coordinate is validated against the Natural Earth boundary for Croatia; results outside it are rejected before payment.

## Output

A numeric value representing the difference between the maximum and minimum sampled surface elevations (local relief) at the given coordinate within Croatia. Coordinates outside Croatia's Natural Earth boundary are rejected before any payment is charged.

## 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-croatia-local-relief-c8788a61/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)