frogcat/20150919.html

## 20150919.html
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>dem</title>
</head>
<body>
	<pre id="pre">Please wait</pre>
	<script>
		function elevation(json, callback) {
			var llz2zxy = function(lat, lon, z) {
				var r = lat * Math.PI / 180
				var n = Math.pow(2, z);
				var x = Math.floor(n * ((lon + 180) / 360));
				var y = Math.floor(n * (1 - (Math.log(Math.tan(r) + 1 / Math.cos(r)) / Math.PI)) / 2);
				return [ z, x, y ];
			};

			if (json.encoded_polyline) {
				alert("ToDo : support encoded polyline");
				return;
			}

			if (json.shape && json.shape.length != 1) {
				alert("ToDo : support multi point shape.");
				return;
			}

			var lat = json.shape[0].lat;
			var lon = json.shape[0].lon;

			var zxy14 = llz2zxy(lat, lon, 14);
			var zxy22 = llz2zxy(lat, lon, 22);
			var url = "http://cyberjapandata.gsi.go.jp/xyz/dem/" + zxy14.join("/") + ".txt";
			var xhr = new XMLHttpRequest();
			xhr.onload = function() {
				var x = zxy22[1] % 256;
				var y = zxy22[2] % 256;
				var h = parseFloat(xhr.responseText.split("\n")[y].split(",")[x]);

				// ToDo : support range
				callback({
					shape : json.shape,
					height : [ h ]
				});
			};
			xhr.open("get", url, true);
			xhr.send();
		}

		elevation({
			"shape" : [ {
				"lat" : 35.6184,
				"lon" : 139.2143
			} ]
		}, function(json) {
			document.getElementById("pre").innerHTML = JSON.stringify(json, null, "  ");
		});
	</script>
</body>
</html>
	<!doctype html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>dem</title>
	</head>
	<body>
	<pre id="pre">Please wait</pre>
	<script>
	function elevation(json, callback) {
	var llz2zxy = function(lat, lon, z) {
	var r = lat * Math.PI / 180
	var n = Math.pow(2, z);
	var x = Math.floor(n * ((lon + 180) / 360));
	var y = Math.floor(n * (1 - (Math.log(Math.tan(r) + 1 / Math.cos(r)) / Math.PI)) / 2);
	return [ z, x, y ];
	};

	if (json.encoded_polyline) {
	alert("ToDo : support encoded polyline");
	return;
	}

	if (json.shape && json.shape.length != 1) {
	alert("ToDo : support multi point shape.");
	return;
	}

	var lat = json.shape[0].lat;
	var lon = json.shape[0].lon;

	var zxy14 = llz2zxy(lat, lon, 14);
	var zxy22 = llz2zxy(lat, lon, 22);
	var url = "http://cyberjapandata.gsi.go.jp/xyz/dem/" + zxy14.join("/") + ".txt";
	var xhr = new XMLHttpRequest();
	xhr.onload = function() {
	var x = zxy22[1] % 256;
	var y = zxy22[2] % 256;
	var h = parseFloat(xhr.responseText.split("\n")[y].split(",")[x]);

	// ToDo : support range
	callback({
	shape : json.shape,
	height : [ h ]
	});
	};
	xhr.open("get", url, true);
	xhr.send();
	}

	elevation({
	"shape" : [ {
	"lat" : 35.6184,
	"lon" : 139.2143
	} ]
	}, function(json) {
	document.getElementById("pre").innerHTML = JSON.stringify(json, null, " ");
	});
	</script>
	</body>
	</html>