# HALOWERK Eastern Land – Bulgaria Depression Depth

> HALOWERK Eastern Land – Bulgaria Depression Depth 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 positive difference between the neighborhood mean elevation and the center cell elevation for a coordinate in Bulgaria, quantifying how deep a topographic depression is.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/bg-depression-depth
- 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-bulgaria-depression-depth-7ee398b7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Y2leBMynOyXV-uIDL3I6x

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-depression-depth-7ee398b7 -d '<json body>'
```

Example prompt: What's the depression depth at latitude 42.35, longitude 23.78 in Bulgaria — I need to know how much lower that point is than its surrounding neighborhood elevation.

## When to prefer this

Use this endpoint when you need a precise, Bulgaria-specific topographic depression depth metric — the positive excess of neighborhood mean elevation over center elevation — for applications like hydrological sink identification, agricultural drainage assessment, or terrain characterization within Bulgaria. Prefer this over generic elevation APIs when you specifically need the depression depth (not raw elevation) and your point of interest is confirmed to be within Bulgaria.

## Known failure modes

- Coordinate outside Bulgaria boundary — request rejected before payment is processed
- Latitude or longitude out of the European coverage range (lat 34–72.5, lon -31.5–40.5) — validation error
- Invalid or missing coordinates — schema validation failure
- Non-positive depression (location is elevated relative to surroundings) — may return zero or be rejected

## How this service works

Positive difference between the neighborhood mean and center elevation. The coordinate is validated against the Natural Earth boundary for Bulgaria; results outside it are rejected before payment.

## Output

A numeric value representing the positive difference between the neighborhood mean surface elevation and the center cell elevation at the queried coordinate, indicating how deep the terrain depression is at that point. Returns an error if the coordinate falls outside Bulgaria'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-eastern-land-bulgaria-depression-depth-7ee398b7/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)