@graphile/postgis

@graphile/postgis

This is a PostGraphile schema plugin that provides support for the popular PostGIS spatial database system.

Create a PostgreSQL database with PostGIS columns, run PostGraphile with this plugin, and have a fully functional geospatial-aware GraphQL API for your database.

Roadmap

Work is ongoing, here's the plan:

• Read-only support for geojson field from all geography types (via a shared GraphQL interface)
• Add GraphQL types for all the expected geography types (implementing this interface)
• Read-only support for determining the geometry sub-types of columns and exposing these directly (rather than the interface)
• Read-only support for longitude and latitude on geography(POINT) columns
• Read-only support for viewing the list of geometries in a geography(GEOMETRYCOLLECTION)
• Read-only support for a list of points (longitude and latitude) on geography(LINESTRING) and geography(POLYGON) columns
• Create/update/null support for geography(POINT) columns
• Create/update/null support for geography(LINESTRING) and geography(POLYGON) columns
• Integration with postgraphile-plugin-connection-filter to enable PostGIS specific filtering (via postgraphile-plugin-connection-filter-postgis)
• Read-only support for computed attributes on geography(LINESTRING) and geography(POLYGON), such as area, length, perimeter, and centroid - currently possible by adding a plugin and consuming the GeoJSON directly.

There are many, many other features that this plugin could support - if you have specific needs please get in touch!

Usage

This plugin requires PostGraphile v4.4.0 or higher to function correctly.

Add PostGIS to your database:

CREATE EXTENSION IF NOT EXISTS postgis WITH SCHEMA public;

Load the plugin:

postgraphile --append-plugins @graphile/postgis

Querying and mutating

Using this table as example:

CREATE TABLE data (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v1mc(),
  geom_point geometry(Point, 4326) default null
);

In queries geom_point is represented as type GeometryPoint. Example:

query {
  allDatas {
    nodes {
      geomPoint {
        geojson
        srid
        x
        y
      }
    }
  }
}

In mutations geom_point is represented as type GeoJSON. Example:

mutation ($id: UUID!, $geomPoint: GeoJSON!) {
  updateDataById(
    input: {
      id: $id,
      dataPatch: {
        geomPoint: $geomPoint
      }
    }
  ) { ... }
}

with these variables:

{
  "id": "0116254a-0146-11ea-8418-4f89d6596247",
  "geomPoint": {
    "type": "Point",
    "coordinates": [8.5, 47.5]
  }
}

Beware of the fact that since 2016 the GeoJSON spec expects the coordinates to be of SRID 4326/WGS84 (see https://tools.ietf.org/html/rfc7946#section-4). So adding a crs field to the GeoJSON is deprecated. Thus since v3 PostGIS will be happy to receive above GeoJSON.

In earlier versions PostGIS expects a SRID to be passed. So the variables would be:

{
  "id": "0116254a-0146-11ea-8418-4f89d6596247",
  "geomPoint": {
    "type": "Point",
    "coordinates": [8.5, 47.5],
    "crs": {
      "type": "name",
      "properties": {
        "name": "urn:ogc:def:crs:EPSG::4326"
      }
    }
  }
}

Development

Contributions are extremely welcome! To get started, clone down this repo and then:

createdb graphile_test
export TEST_DATABASE_URL=postgres://localhost:5432/graphile_test
yarn
yarn dev

Note the development server runs at http://localhost:5123/graphiql

To run the tests:

yarn test