offline-geocode-city

217 kB, tiny offline reverse geocoding library that works anywhere, browser, Node.js, web worker. High performance (S2 cell based). Looks up country and nearest city, given GPS coordinates

Features

✅ Reverse geocodes offline
✅ Works in all JS environments (browser, Node.js, service worker etc.)
✅ Not only Country and ISO2, but also nearest city geocoded
✅ Only 217 kB nano sized (ESM, gizpped) (alternatives are ~`20 MiB`)
✅ World record smallest size for city reverse geocoding
✅ World record performance for reverse geocoding using S2 cell
✅ Available as a simple API
✅ Tree-shakable and side-effect free
✅ First class TypeScript support

Example usage (API)

Setup

yarn: yarn add offline-geocode-city
npm: npm install offline-geocode-city

ESM

import { getNearestCity } from 'offline-geocode-city'

const nearestCity = getNearestCity(48.3243193, 11.658644)

deepEqual(nearestCity, {
    cityName: 'Ismaning',
    countryIso2: 'DE',
    countryName: 'Germany'
})

This library can be used to lookup the nearest city in-browser using the GeoLocation web api (offline):

const getLocation = (): Promise<GeolocationResult> =>
    new Promise((resolve, reject) => {
        if (navigator.geolocation) {
            navigator.geolocation.getCurrentPosition(resolve, reject);
        } else {
            reject(new Error('Geolocation is not supported by this browser.'));
        }
    });

const position = await getLocation()

 if (position instanceof Error) {
    console.error(position.message);
} else {

    console.log(`Latitude: ${(position.coords.latitude)}`);
    console.log(`Longitude: ${(position.coords.longitude)}`);

    const nearestCity = getNearestCity(position.coords.latitude, position.coords.longitude)

    console.log('nearestCity', nearestCity)
}