Computing bounds from latitude and longitude and size [meters]

bounds.ts

export function createBoundsFromLocationAndSize(
	location: Location,
	width: number,
	height: number
): Bounds {
	const diagonal: number = Math.sqrt(width * width + height * height);
	const alpha: number = toDegrees(Math.asin(height / diagonal));
	const sw: Location = locationWithOffset(location, diagonal, 270 - alpha);
	const ne: Location = locationWithOffset(location, diagonal, 90 - alpha);
	return {
		south: sw.lat,
		west: sw.lng,
		north: ne.lat,
		east: ne.lng
	} as Bounds;
}

function locationWithOffset(location: Location, distance: number, heading: number): Location {
	heading = toRadians(heading);
	const latRad: number = toRadians(location.lat);
	const lngRad: number = toRadians(location.lng);
	const dR: number = distance / EARTH_RADIUS; // radius of the Earth in meters
	const finalLat: number = Math.asin(
		Math.sin(latRad) * Math.cos(dR) + Math.cos(latRad) * Math.sin(dR) * Math.cos(heading)
	);
	const finalLng: number = lngRad + Math.atan2(
		Math.sin(heading) * Math.sin(dR) * Math.cos(latRad), Math.cos(dR) - Math.sin(latRad) * Math.sin(finalLat)
	);
	return {
		lat: toDegrees(finalLat),
		lng: toDegrees(finalLng)
	};
}

function toRadians(degrees: number): number {
	return degrees * Math.PI / 180;
}

function toDegrees(radians: number): number {
	return radians * 180 / Math.PI;
}