# `Feature`

A GeoJSON `Feature`: a geometry of the type `G`, one of the six or `Geometry`, and properties of the application's `Object` type `P`, sent as RFC 7946 writes one, with no `id`: `Feature<Polygon, PatchProperties>`.

[Geospatial](types.md#geospatial); not ordered; since Jadpo 0.1.0.

## Make one

Build one from its fields, `Feature { geometry: ...  properties: ... }`.

## Fields

| Field | Type |
|---|---|
| `geometry` | `G` |
| `properties` | `P` |

## Text, JSON and storage

It has no single text form, so `text.from` and `text.parse` don't take it. JSON sends a GeoJSON object of its geometry and properties.

| JSON |
|---|
| `{"type":"Feature","geometry":{"type":"Point","coordinates":[-0.1276,51.5072]},"properties":{"name":"Site A"}}` |

It is stored in one column named for the field, of type `jsonb`. `{"type":"Feature","geometry":{"type":"Point","coordinates":[-0.1276,51.5072]},"properties":{"name":"Site A"}}` is stored as `'{"type":"Feature","geometry":{"type":"Point","coordinates":[-0.1276,51.5072]},"properties":{"name":"Site A"}}'::jsonb`.

## Shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `{"type":"Feature","geometry":{"type":"Point","coordinates":[-0.1276,51.5072]},"properties":{"name":"Site A"}}` | `""` |

## Operations

It has the contract's own operations: `text.format`, `json.read`, `json.write` and `==`. It isn't ordered, so `<` and sorting don't take it. [Every standard type meets one contract](../topics/every-standard-type-meets-one-contract.md) says how they work.