# HALOWERK Baltic Land – Estonia Maximum Surface Slope

> HALOWERK Baltic Land – Estonia Maximum 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) at a given coordinate within Estonia's boundaries.

## Facts

- Endpoint: POST https://baltikum.halowerk.com/v1/ee-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-estonia-maximum-surface-slope-f79dc240
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_I9_qAhucG-68lU9xKZoEl

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-estonia-maximum-surface-slope-f79dc240 -d '<json body>'
```

Example prompt: What's the maximum terrain slope at latitude 58.3780, longitude 26.7290 in Estonia? I need the steepest surface gradient for that point.

## When to prefer this

Use this endpoint when you need point-level maximum terrain slope data specifically within Estonia. It is ideal for geospatial enrichment pipelines, site feasibility studies, agricultural suitability assessments, or hydrological modeling where Estonia-validated slope data is required. Prefer it over generic DEM APIs when boundary validation and per-query micropayment pricing are acceptable and Estonia coverage is sufficient.

## Known failure modes

- Coordinate outside Estonia's Natural Earth boundary — request rejected with validation error before payment
- Latitude or longitude outside the published European coverage bounds (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Missing required latitude or longitude field — request returns validation/bad request error
- Network or service timeout — transient error, retry recommended
- Payment failure via x402 protocol — request not processed

## How this service works

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

## Output

A numeric value representing the maximum adjacent-cell surface slope gradient (steepest local terrain angle or rise-over-run) at the queried coordinate within Estonia. Coordinates outside Estonia'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-estonia-maximum-surface-slope-f79dc240/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)