Downloads and stitches map tiles

Google Maps Satellie Tile Fetcher.js

// For a given latitude, longitude, and zoom, returns the URL to an image for that tile.

function tileIndex(latitude, longitude, zoom){
	if ((latitude === undefined) || (longitude === undefined) || (zoom === undefined))
		throw("Arguments mising in tileIndex");
	
	var lat_rad = latitude / 180 * Math.PI;
	var n = 1 << zoom;
	var xtile = n * ((longitude + 180) / 360);
	var ytile = n * (1 - (Math.log (Math.tan (lat_rad) + 1/Math.cos (lat_rad)) / Math.PI)) / 2;

	return [Math.floor(xtile), Math.floor(ytile)]
}

function satelliteImage(latitude, longitude, zoom){
	const Server = 'khms2'
	const Version = 923
	
	var [x, y] = tileIndex(latitude, longitude, zoom)
	return 'https://' + Server + '.google.com/kh/v=' + Version + '?x=' + x + '&y=' + y + '&z=' + zoom

}

// Test: satelliteImage(51.4733514399, -0.00088499646, 15)