> ## Documentation Index
> Fetch the complete documentation index at: https://astral-6ef288be-docs-policy-evaluation-framing.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# GeoJSON

> Raw unsigned geospatial data — the simplest input format

<Note>**Research Preview** — APIs may change. [GitHub](https://github.com/AstralProtocol)</Note>

# GeoJSON

GeoJSON is raw, unsigned geospatial data. It's the simplest way to pass location data into Astral — and the least verifiable.

## The format

GeoJSON ([RFC 7946](https://datatracker.ietf.org/doc/html/rfc7946)) is a standard format for encoding geographic data structures. The full spec defines three object types — Geometry, Feature (geometry + properties), and FeatureCollection — but **Astral v0 works with bare Geometry objects only**, not Feature or FeatureCollection wrappers.

A Geometry object has two keys:

* **`type`** — the geometry type: `Point`, `LineString`, `Polygon`, `MultiPoint`, `MultiLineString`, `MultiPolygon`, or `GeometryCollection`
* **`coordinates`** — nested arrays of `[longitude, latitude]` positions

Geometries are built from coordinate arrays. A Point is a single `[lon, lat]` pair. A LineString is an array of positions. A Polygon is an array of linear rings — where each ring is an array of positions and the **first and last position must be identical** (closing the ring to form a valid area).

```json theme={null}
{
  "type": "Polygon",
  "coordinates": [[
    [-122.42, 37.78],
    [-122.42, 37.76],
    [-122.40, 37.76],
    [-122.40, 37.78],
    [-122.42, 37.78]
  ]]
}
```

<Warning>
  Astral APIs accept **bare Geometry objects** — pass the geometry directly, not wrapped in a Feature. If you're exporting from tools like geojson.io, extract the `geometry` field from the Feature before passing it to Astral.
</Warning>

## What GeoJSON does not provide

* **Attribution** — No record of who created it
* **Integrity** — No way to detect if it's been modified
* **Correspondence** — No evidence that it reflects reality

A signed result that uses raw GeoJSON as input proves "Astral computed the relationship between geometry A and geometry B" — but it does not prove who provided those geometries or whether they correspond to anything in the physical world.

For inputs where provenance matters, use [signed location records](/concepts/location-records) or [location proofs](/concepts/location-proofs).

## Coordinate conventions

| Convention           | Value                                                   |
| -------------------- | ------------------------------------------------------- |
| **Format**           | GeoJSON (RFC 7946)                                      |
| **CRS**              | WGS84 (`http://www.opengis.net/def/crs/OGC/1.3/CRS84`)  |
| **Coordinate order** | `[longitude, latitude]`                                 |
| **Altitude**         | Optional third coordinate, meters above WGS84 ellipsoid |

<Warning>
  Many mapping APIs use `[latitude, longitude]` order. GeoJSON uses `[longitude, latitude]`. Mixing these up is a common source of bugs — your point ends up in the wrong hemisphere.
</Warning>

## Tools for working with GeoJSON

* **[geojson.io](https://geojson.io)** — Draw, edit, and export GeoJSON on a map. The standard quick-start tool.
* **[Placemark Play](https://play.placemark.io)** — Open-source geodata editor with drawing and algorithmic operations (buffering, simplification).
* **[MapShaper](https://mapshaper.org)** — Simplify, convert, and inspect vector data. Useful for reducing file size and format conversion.

<Card title="Next: Location records" icon="file-signature" href="/concepts/location-records">
  Signed, verifiable location data
</Card>

***

**See also:**

* [API: Types — Input](/api-reference/types) — how raw GeoJSON is passed to API endpoints