> ## Documentation Index
> Fetch the complete documentation index at: https://docs-attestly.code4source.com/llms.txt
> Use this file to discover all available pages before exploring further.

# POST /v1/intersections

> List reference areas that overlap a geometry.

A discovery endpoint: send a polygon, get back every reference area
that intersects it, with overlap area and ratios.

## Request

```json theme={null}
{
  "input": {
    "geometry": {
      "type": "Polygon",
      "coordinates": [[[-60,-3],[-60,-2],[-59,-2],[-59,-3],[-60,-3]]]
    },
    "crs": "EPSG:4326"
  },
  "reference_areas_source": "icmbio_ucs_federais",
  "reference_areas_country_iso3": "BRA",
  "reference_id": "deal-12345"
}
```

| Field                          | Required | Notes                                               |
| ------------------------------ | -------- | --------------------------------------------------- |
| `input.geometry`               | yes      | GeoJSON. Must be valid.                             |
| `input.crs`                    | no       | Source CRS. Default: `EPSG:4326`.                   |
| `reference_areas_source`       | no       | Restrict to one source. Omit to query all.          |
| `reference_areas_country_iso3` | no       | Filter sources by country (ISO 3166-1 alpha-3).     |
| `reference_id`                 | no       | Caller-provided correlation id, echoed in response. |

## Response

```json theme={null}
{
  "data": {
    "intersections": [
      {
        "source_name": "icmbio_ucs_federais",
        "source_id": "uc-042",
        "name": "Parque Nacional da Amazônia",
        "country_iso3": "BRA",
        "properties": { ... },
        "overlap_area_m2": 1234567.8,
        "overlap_pct_input": 0.42,
        "overlap_pct_feature": 0.03
      }
    ],
    "reference_areas_check": "ok",
    "reference_id": "deal-12345"
  },
  "meta": { "request_id": "..." },
  "errors": []
}
```

`reference_areas_check` is `"ok"` when all sources answered, `"failed"`
when a partial answer was returned because at least one source could
not be reached.

`overlap_pct_input` is the fraction of your input geometry covered by
the matching feature; `overlap_pct_feature` is the fraction of the
matching feature covered by your input.

See the **OpenAPI** tab in the sidebar for the complete request/response
schema.