Web Mercator projection (e.g. ImageMapTypeOptions.getTitleUrl)

gistfile1.txt

		const project = ( latLng: google.maps.LatLng, zoom: number ) => {
			const scale = Math.pow( 2, zoom );
			const lambda = latLng.lng() / 180 * Math.PI;
			const phi = latLng.lat() / 180 * Math.PI;
			return new google.maps.Point(
				256 / 2 / Math.PI * scale * ( lambda + Math.PI ),
				256 / 2 / Math.PI * scale * ( Math.PI - Math.log( Math.tan( Math.PI / 4 + phi / 2 ) ) )
			);
		}

		const unproject = ( point: google.maps.Point, zoom: number ) => {
			const scale = Math.pow( 2, zoom );
			const lambda = point.x / ( 256 / 2 / Math.PI * scale ) - Math.PI;
			const phi = ( Math.atan( Math.exp( Math.PI - point.y / ( 256 / 2 / Math.PI * scale ) ) ) - Math.PI / 4 ) * 2;
			return new google.maps.LatLng(
				phi / Math.PI * 180,
				lambda / Math.PI * 180
			);
		}