# HALOWERK Baltic Land – Poland Max Surface Slope

> HALOWERK Baltic Land – Poland Max Surface Slope is a paid API for AI agents from baltikum.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns the maximum adjacent-cell surface gradient (steepest slope) across the analysis grid for a given coordinate within Poland.

## Facts

- Endpoint: POST https://baltikum.halowerk.com/v1/pl-max-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-baltic-land-poland-max-surface-slope-59b852c9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_f92DWtowgQi0lM6qQ9MJE

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-baltic-land-poland-max-surface-slope-59b852c9 -d '<json body>'
```

Example prompt: What's the maximum surface slope gradient at latitude 52.23, longitude 21.01 in Poland — I need the steepest adjacent-cell gradient value for that location.

## When to prefer this

Use this endpoint when you specifically need the steepest slope metric (maximum adjacent-cell surface gradient) for a point in Poland. Prefer it over general elevation APIs when slope extremity — not mean elevation or average ruggedness — is the required output. It is well-suited for construction suitability, erosion risk, drainage routing, or agricultural land screening workflows focused on Polish territory.

## Known failure modes

- Coordinate outside Poland boundary: request rejected before payment, returns validation error
- Latitude or longitude outside published European coverage range (lat 34–72.5, lon -31.5–40.5): schema validation failure
- Malformed or missing coordinate fields: 400-level error
- Temporary upstream terrain data unavailability: 5xx error

## How this service works

Maximum adjacent-cell surface gradient across the analysis grid. The coordinate is validated against the Natural Earth boundary for Poland; results outside it are rejected before payment.

## Output

A scalar value representing the maximum adjacent-cell surface gradient (steepest slope) across the analysis grid centered on the requested coordinate within Poland. Coordinates outside Poland's Natural Earth boundary are rejected before any charge is made.

## 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-baltic-land-poland-max-surface-slope-59b852c9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from baltikum.halowerk.com](https://www.zero.xyz/host/baltikum.halowerk.com/llms.txt)