@panoramax/web-viewer/src/utils/geocoder.js

Panoramax web viewer for geolocated pictures

import { NominatimBaseUrl, AdresseDataGouvBaseURL } from "./services";

const PLACETYPE_ZOOM =  {
	"house": 20,
	"housenumber": 20,
	"street": 18,
	"locality": 15,
	"district": 13,
	"municipality": 12,
	"city": 12,
	"county": 8,
	"region": 7,
	"state": 7,
	"country": 5
};

/**
 * Transforms a set of parameters into an URL-ready string
 * It also removes null/undefined values
 *
 * @param {object} params The parameters object
 * @return {string} The URL query part
 * @private
 */
function geocoderParamsToURLString(params) {
	let p = {};
	Object.entries(params)
		.filter(e => e[1] !== undefined && e[1] !== null)
		.forEach(e => p[e[0]] = e[1]);

	return new URLSearchParams(p).toString();
}

/**
 * Nominatim (OSM) geocoder, ready to use for our Map
 * @private
 */
export function forwardGeocodingNominatim(config) {
	// Transform parameters into Nominatim format
	const params = {
		q: config.query,
		countrycodes: config.countries,
		limit: config.limit,
		viewbox: config.bbox,
	};

	return fetch(`${NominatimBaseUrl()}/search?${geocoderParamsToURLString(params)}&format=geocodejson&addressdetails=1`)
		.then(res => res.json())
		.then(res => {
			const finalRes = { features: [] };
			const listedNames = [];
			(res.features || []).forEach(f => {
				const plname = geocodeJsonToPlaceName(f.properties?.geocoding) || f.properties?.geocoding?.label;
				if(!listedNames.includes(plname)) {
					finalRes.features.push({
						place_type: ["place"],
						place_name: plname,
						center: f.geometry.coordinates,
						zoom: PLACETYPE_ZOOM[f.properties?.geocoding?.type],
					});
					listedNames.push(plname);
				}
			});
			return finalRes;
		});
}

export function reverseGeocodingNominatim(lat, lon) {
	return fetch(`${NominatimBaseUrl()}/reverse?lat=${lat}&lon=${lon}&zoom=18&format=geocodejson`)
		.then(res => res.json())
		.then(res => geocodeJsonToPlaceName(res?.features?.shift()?.properties?.geocoding));
}

/**
 * Base adresse nationale (FR) geocoder, ready to use for our Map
 * @param {object} config Configuration sent by MapLibre GL Geocoder, following the geocoderApi format ( https://maplibre.org/maplibre-gl-geocoder/types/MaplibreGeocoderApiConfig.html )
 * @returns {object} GeoJSON Feature collection in Carmen GeoJSON format ( https://maplibre.org/maplibre-gl-geocoder/types/CarmenGeojsonFeature.html )
 * @private
 */
export function forwardGeocodingBAN(config) {
	return forwardGeocodingStandard(config, AdresseDataGouvBaseURL());
}

/**
 * Transforms GeocodeJSON search result into a nice-to-display address.
 * @param {object} props The GecodeJSON API feature properties
 * @returns {string} The clean-up string for display
 * @private
 */
function geocodeJsonToPlaceName(props) {
	// API format @ https://github.com/geocoders/geocodejson-spec/blob/master/draft/README.md
	if(!props || typeof props != "object") { return ""; }

	// P1 = main name, P2=locality-like, P3=country+high-level admin
	let p1 = props.name;
	let p2 = [], p3 = [];

	switch(props.type) {
	case "hamlet":
	case "croft":
	case "isolated_dwelling":
	case "neighbourhood":
	case "allotments":
	case "quarter":
	case "farm":
	case "farmyard":
	case "industrial":
	case "commercial":
	case "retail":
	case "city_block":
	case "residential":
	case "locality":
	case "district":
		p3.push(props.city);
		p3.push(props.county);
		p3.push(props.state);
		p3.push(props.country);
		break;
	case "city":
		p3.push(props.county);
		p3.push(props.state);
		p3.push(props.country);
		break;
	case "region":
		p3.push(props.county);
		p3.push(props.state);
		p3.push(props.country);
		break;
	case "country":
		break;
	case "house":
	case "housenumber":
		p2.push(props.housenumber);
		p2.push(props.street);
		p2.push(props.locality);
		p2.push(props.district);
		p3.push(props.city);
		p3.push(props.county);
		p3.push(props.state);
		p3.push(props.country);
		break;
	case "street":
	case "road":
	default:
		p2.push(props.street);
		p2.push(props.locality);
		p2.push(props.district);
		p3.push(props.city);
		p3.push(props.county);
		p3.push(props.state);
		p3.push(props.country);
		break;
	}

	p2 = p2.filter(v => v);
	p2 = p2.filter((v,i) => v != p1 && (i === 0 || p2[i-1] !== v));
	p2 = p2.length > 0 ? (props.housenumber ? p2.slice(0,2).join(" ") : p2.shift()) : null;
	if(p2 === p1) { p2 = null; }

	p3 = p3.filter(v => v);
	p3 = p3.filter((v,i) => v != p1 && (!p2 || !p2.includes(v)) && (i === 0 || p3[i-1] !== v));

	let res = [p1, p2, p3.shift()].filter(v => v);

	return res.join(", ");
}

/**
 * Standard forward geocoder
 * @param {object} config Configuration sent by MapLibre GL Geocoder, following the geocoderApi format ( https://maplibre.org/maplibre-gl-geocoder/types/MaplibreGeocoderApiConfig.html )
 * @param {string} endpoint The URL endpoint (everything before the /?q=...)
 * @returns {object} GeoJSON Feature collection in Carmen GeoJSON format ( https://maplibre.org/maplibre-gl-geocoder/types/CarmenGeojsonFeature.html )
 * @private
 */
export function forwardGeocodingStandard(config, endpoint) {
	// Transform parameters into BAN format
	const params = { q: config.query, limit: config.limit };
	if(typeof config.proximity === "string") {
		const [lat, lon] = config.proximity.split(",").map(v => parseFloat(v.trim()));
		params.lat = lat;
		params.lon = lon;
	}

	return fetch(`${endpoint}/?${geocoderParamsToURLString(params)}`)
		.then(res => res.json())
		.then(res => {
			const finalRes = { features: [] };
			const listedNames = [];
			(res.features || []).forEach(f => {
				const plname = geocodeJsonToPlaceName(f.properties);
				if(!listedNames.includes(plname) && f.properties.type != "other") {
					finalRes.features.push({
						place_type: ["place"],
						place_name: plname,
						center: f.geometry.coordinates,
						zoom: PLACETYPE_ZOOM[f.properties.type],
					});
					listedNames.push(plname);
				}
			});
			return finalRes;
		});
}