# HALOWERK Eastern Land – Croatia Elevation Lookup

> HALOWERK Eastern Land – Croatia Elevation Lookup 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 bilinear-interpolated surface elevation (metres) for a WGS84 coordinate inside Croatia using Copernicus DEM GLO-30, rejecting coordinates outside Croatian boundaries before charging.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/hr-elevation
- 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-elevation-lookup-b9bdbb72
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZIoVUA7z9YOl5VckkXlx5

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-elevation-lookup-b9bdbb72 -d '<json body>'
```

Example prompt: What is the surface elevation at latitude 45.8150 and longitude 15.9819 in Croatia — pull it from the Copernicus GLO-30 DEM?

## When to prefer this

Choose this endpoint when you need precise, Copernicus GLO-30-based surface elevation for a specific point within Croatia and want boundary pre-validation to avoid paying for out-of-scope coordinates. Prefer it over general-purpose elevation APIs when Croatia-specific validation and per-call micro-payment via x402 are acceptable, and when bilinear interpolation quality from a 30m DEM is sufficient for your use case.

## Known failure modes

- Coordinate outside Croatia boundary — rejected before payment with a 4xx error indicating the point falls outside the validated region
- Coordinate within European coverage bounds but outside Croatia — rejected by Natural Earth boundary check
- Invalid latitude/longitude values outside the published European range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Service unavailability or upstream DEM data error — 5xx response

## How this service works

Bilinear surface elevation from Copernicus DEM GLO-30. The coordinate is validated against the Natural Earth boundary for Croatia; results outside it are rejected before payment.

## Output

A bilinear-interpolated surface elevation value in metres above sea level for the requested WGS84 coordinate, derived from the Copernicus DEM GLO-30 30-metre resolution dataset. Coordinates outside the Croatian boundary are rejected before the payment is processed.

## 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-elevation-lookup-b9bdbb72/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)