# HALOWERK Eastern Land – Bulgaria Local Relief

> HALOWERK Eastern Land – Bulgaria 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 2026-09-13).

Returns the difference between maximum and minimum sampled surface elevation (local relief) for a WGS84 coordinate within Bulgaria.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/bg-local-relief
- 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-eastern-land-bulgaria-local-relief-14e1e16d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_b14gZEgSxz3PCpt4ypJpd

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-bulgaria-local-relief-14e1e16d -d '<json body>'
```

Example prompt: What's the local relief — the difference between the highest and lowest surface elevation — at latitude 42.698 and longitude 23.322 in Bulgaria?

## When to prefer this

Use this endpoint when you need the local topographic relief (max minus min elevation) specifically for a point within Bulgaria, and require boundary-validated results. Prefer it over generic elevation APIs when you need guaranteed geographic scoping to Bulgaria with pre-payment coordinate validation, and when working within an x402 micropayment workflow at low per-call cost.

## Known failure modes

- Coordinate outside Bulgaria boundary — rejected before payment with validation error
- Latitude or longitude out of European coverage range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Malformed or missing coordinate fields — 400-level error
- Service unavailability or upstream elevation data failure — 5xx error

## How this service works

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

## Output

Returns a single numeric value representing the local relief — the difference in meters between the maximum and minimum sampled surface elevation within the analysis grid around the given coordinate. Coordinates outside the Natural Earth boundary of Bulgaria 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-bulgaria-local-relief-14e1e16d/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)