postgis

A lightweight, type-safe Node.js library for interacting with PostGIS-enabled PostgreSQL databases. Export GeoJSON, serve MVT vector tiles, run spatial queries, and more — with zero runtime dependencies.

📖 Full Documentation →

Features

| Feature | Details | |---|---| | 🔷 TypeScript First | Full type definitions, IntelliSense, and compile-time safety | | 📦 Dual ESM + CJS | Tree-shakable ESM + CommonJS fallback — works everywhere | | ⚡ Zero Runtime Deps | Bring your own pg client, nothing else required | | 🗺️ Spatial Queries | bbox, centroid, intersections, nearest, coordinate transforms | | 📄 GeoJSON Export | Full FeatureCollection with bounds, ID, and precision control | | 🗜️ Geobuf Export | Binary-compact protobuf encoding via ST_AsGeobuf | | 🧱 MVT Tiles | Server-side Mapbox Vector Tiles via ST_AsMVT | | 🧪 Fully Tested | 50+ unit tests with mocked pg.Client — no database needed |

Installation

npm install postgis pg

yarn add postgis pg

pnpm add postgis pg

Requirements: Node.js ≥ 18, PostgreSQL ≥ 12, PostGIS ≥ 3.0

Quick Start

import { Client } from 'pg';
import Postgis from 'postgis';

const client = new Client({ connectionString: process.env.DATABASE_URL });
await client.connect();

const postgis = new Postgis(client);

// List spatial tables
const tables = await postgis.list_tables();

// Export as GeoJSON
const fc = await postgis.geojson('parcels', { precision: 6, columns: 'name, area' });
console.log(fc.type); // "FeatureCollection"

// Find 5 nearest hospitals
const nearby = await postgis.nearest('hospitals', '73.5,14.9,4326', { limit: 5 });

await client.end();

CommonJS:

const Postgis = require('postgis');
const postgis = new Postgis(client);

API Documentation

Constructor

new Postgis(client: PostgisClient)

Accepts any pg.Client, pg.Pool client, or any object with a query(sql) method.

list_tables(options?)

Lists all user-accessible tables with PostGIS geometry metadata.

const tables = await postgis.list_tables({ filter: "table_type = 'BASE TABLE'" });

list_columns(table)

Lists all columns of a table using PostgreSQL system catalogs.

const cols = await postgis.list_columns('parcels');
// [{ field_name: 'geom', field_type: 'geometry' }, ...]

query_table(table, options?)

Flexible SELECT with filter, group, sort, and limit.

const rows = await postgis.query_table('parcels', {
  columns: 'id, name',
  filter: "status = 'active'",
  sort: 'name ASC',
  limit: 50,
});

bbox(table, options?)

Returns the spatial bounding box (ST_Extent) of all geometries.

const [{ bbox }] = await postgis.bbox('parcels', { srid: 4326 });

centroid(table, options?)

Returns the centroid (x, y) of each geometry.

const pts = await postgis.centroid('parcels', { force_on_surface: true });

intersect_feature(table_from, table_to, options?)

Cross-table spatial intersection using ST_DWithin.

const hits = await postgis.intersect_feature('roads', 'parcels', { distance: '50' });

intersect_point(table, point, options?)

Features within distance of a point.

// point format: "longitude,latitude,SRID"
const nearby = await postgis.intersect_point('shops', '73.5,14.9,4326', {
  distance: '500',
  limit: 20,
});

geojson(table, options?)

Exports a GeoJSON FeatureCollection.

const fc = await postgis.geojson('parcels', {
  bounds: '72.8,18.9,73.2,19.2',  // xmin,ymin,xmax,ymax
  precision: 6,
  columns: 'name, area',
});
// { type: 'FeatureCollection', features: [...] }

geobuf(table, options?)

Exports features as a Geobuf binary Buffer.

const buf = await postgis.geobuf('parcels');
res.setHeader('Content-Type', 'application/x-protobuf');
res.send(buf);

mvt(table, x, y, z, options?)

Generates a Mapbox Vector Tile for tile coordinate z/x/y.

const [{ mvt }] = await postgis.mvt('parcels', 0, 0, 0);
res.setHeader('Content-Type', 'application/vnd.mapbox-vector-tile');
res.send(mvt);

nearest(table, point, options?)

KNN nearest-neighbor search ordered by <-> distance operator.

const closest = await postgis.nearest('hospitals', '73.5,14.9,4326', { limit: 5 });
// Each row includes a `distance` column

transform_point(point, options?)

Transforms a point between coordinate systems.

const [{ x, y }] = await postgis.transform_point('73.5,14.9,4326', { srid: 3857 });

Configuration

Environment Variables

| Variable | Description | |---|---| | DATABASE_URL | PostgreSQL connection string | | POSTGIS_DEBUG | Set to 'true' to log all SQL queries to stderr |

Point Format

Methods accepting a point argument use "x,y,srid" format:

73.70534,14.94202,4326  →  longitude,latitude,EPSG:4326

Advanced Usage

MVT Tile Server (Express)

app.get('/tiles/:z/:x/:y.mvt', async (req, res) => {
  const client = await pool.connect();
  try {
    const postgis = new Postgis(client);
    const [row] = await postgis.mvt('parcels', +req.params.x, +req.params.y, +req.params.z);
    if (!row?.mvt) return res.status(204).end();
    res
      .setHeader('Content-Type', 'application/vnd.mapbox-vector-tile')
      .setHeader('Cache-Control', 'public, max-age=3600')
      .send(row.mvt);
  } finally {
    client.release();
  }
});

Using with pg.Pool

const client = await pool.connect();
const postgis = new Postgis(client);
try {
  return await postgis.geojson('my_layer');
} finally {
  client.release();
}

Performance Notes

• Spatial indexes are essential for large tables. Add a GiST index:

  CREATE INDEX ON my_layer USING GIST(geom);

• MVT queries internally call ST_TileEnvelope — PostGIS 3.0+ required.
• Bounds filtering avoids full-table scans when a bounds argument is provided.
• nearest() uses the index-accelerated <-> KNN operator — much faster than ORDER BY ST_Distance.

Security

[!WARNING] SQL values (table names, column names, filters) are interpolated directly into SQL strings — not parameterized. Never pass raw user input as table, filter, or columns arguments.

See SECURITY.md for the full security policy and reporting process.

Examples

See the examples/ directory:

| File | Description | |---|---| | basic-usage.js | List tables, columns, query, bbox | | geojson-export.js | Export GeoJSON and Geobuf to files | | mvt-server.js | Express MVT tile server with Mapbox GL JS viewer |

FAQ

Does it work with pg.Pool? Yes — acquire a client from the pool, pass it to new Postgis(client), and release it after.

CommonJS or ESM? Both. Import with import Postgis from 'postgis' (ESM) or const Postgis = require('postgis') (CJS).

Any runtime dependencies? None. pg is a peer dependency — you install and manage it yourself.

Full FAQ: jsuyog2.github.io/postgis/guide/faq

Contributing

We welcome contributions! Please read CONTRIBUTING.md for guidelines on:

• Setting up the dev environment
• Running tests (npm test)
• Submitting pull requests

Changelog

See CHANGELOG.md for version history.

License

MIT © Suyog Dinesh Jadhav