#OpenStreetMap Provider

For more options and configurations, see the OpenStreetMap Nominatim wiki.

import { OpenStreetMapProvider } from 'leaflet-geosearch';

const provider = new OpenStreetMapProvider();

// add to leaflet
import { GeoSearchControl } from 'leaflet-geosearch';

map.addControl(
  new GeoSearchControl({
    provider,
    style: 'bar',
  }),
);

#Usage policy

The public Nominatim server (nominatim.openstreetmap.org) is free, but it has a usage policy. The short version:

• your app must be identifiable. Browsers send a referer, which is enough. Where that is missing (e.g. in an app built with Electron), add the email parameter.
• search-as-you-type is not allowed on the public server, and it doesn't work well anyway, because Nominatim can't search partial words. Turn off autoComplete on the control, or run your own Nominatim, or use another provider for autocomplete.
• keep the number of requests low. The control can help with minQueryLength, autoCompleteDelay and cacheSize.

The email parameter is not a login and doesn't give you more requests. It lets the Nominatim admins tell your (small) traffic apart from scrapers they need to block.

const provider = new OpenStreetMapProvider({
  params: {
    email: '[email protected]', // identifies your app to the Nominatim admins
  },
});

map.addControl(
  new GeoSearchControl({
    provider,
    autoComplete: false, // search-as-you-type is not allowed on nominatim.openstreetmap.org
  }),
);

#Optional parameters

OpenStreetMap Nominatim supports a number of optional parameters. As the api requires those parameters to be added to the url, they can be added to the params key of the provider.

All options defined next to the params key, would have been added to the request body.

const provider = new OpenStreetMapProvider({
  params: {
    'accept-language': 'nl', // render results in Dutch
    countrycodes: 'nl', // limit search results to the Netherlands
    addressdetails: 1, // include additional address detail parts
    format: 'jsonv2', // the default is json
  },
});

#Limiting the results to an area

Nominatim can leave out results outside an area. With countrycodes it only searches the given countries (ISO 3166-1 alpha-2 codes). With viewbox and bounded: 1 it only searches inside a box, given as west,north,east,south (longitude, latitude):

// the United States and Canada
const countries = new OpenStreetMapProvider({
  params: { countrycodes: 'us,ca' },
});

// a box around the contiguous United States
const box = new OpenStreetMapProvider({
  params: { viewbox: '-125,49,-66,24', bounded: 1 },
});

Without bounded, the viewbox only puts the results inside the box first. Other providers have their own parameters for this, like bbox for Photon or boundary.rect for Pelias, see the page of each provider.