maplair

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JavaScript library for mobile-friendly interactive maps

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JavaScript

import { Point } from "../../geometry/Point.js";
import { Bounds } from "../../geometry/Bounds.js";
import { LatLng } from "../LatLng.js";
//#region src/geo/projection/Projection.SphericalMercator.js
const earthRadius = 6378137;
const SphericalMercator = {
	R: earthRadius,
	MAX_LATITUDE: 85.0511287798,
	project(latlng) {
		latlng = new LatLng(latlng);
		const d = Math.PI / 180, max = this.MAX_LATITUDE, lat = Math.max(Math.min(max, latlng.lat), -max), sin = Math.sin(lat * d);
		return new Point(this.R * latlng.lng * d, this.R * Math.log((1 + sin) / (1 - sin)) / 2);
	},
	unproject(point) {
		point = new Point(point);
		const d = 180 / Math.PI;
		return new LatLng((2 * Math.atan(Math.exp(point.y / this.R)) - Math.PI / 2) * d, point.x * d / this.R);
	},
	bounds: (() => {
		const d = earthRadius * Math.PI;
		return new Bounds([-d, -d], [d, d]);
	})()
};
//#endregion
export { SphericalMercator };

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