further cleanup and testing for #16

README.md

@@ -118,6 +118,13 @@ var key = S2.idToKey(id);
 // '9749618446378729472'
 
 
+//
+// Convert between Quadkey and Id
+//
+var latlng = S2.keyToLatLng(key);
+var latlng = S2.idToLatLng(id);
+
+
 
 //
 // Neighbors
@@ -198,3 +205,12 @@ var hilbertQuadkey = S2.idToKey(cellId);
 
 console.log(hilbertQuadkey);
 ```
+
+Convert Key and Id to LatLng
+---------------------
+
+```javascript
+var latlng = S2.keyToLatLng('4/032212303102210');
+
+var latlng = S2.idToLatLng('9749618446378729472');
+```

src/s2geometry.js

@@ -272,29 +272,31 @@ S2.S2Cell.FromHilbertQuadKey = function(hilbertQuadkey) {
   var point = {
     x : 0,
     y: 0
-  }
+  };
+  var i;
+  var level;
+  var bit;
+  var rx, ry;
+  var val;
 
-	for(var i = maxLevel - 1; i >= 0; i--)
-	{
+	for(i = maxLevel - 1; i >= 0; i--) {
 
-		var level = maxLevel - i;
-		var bit = position[i];
-		var rx = 0, ry = 0;
-		if(bit == '1')
-		{
+		level = maxLevel - i;
+		bit = position[i];
+		rx = 0;
+    ry = 0;
+		if (bit === '1') {
 			ry = 1;
 		}
-		else if(bit == '2')
-		{
+		else if (bit === '2') {
 			rx = 1;
 			ry = 1;
 		}
-		else if(bit == '3')
-		{
+		else if (bit === '3') {
 			rx = 1;
 		}
 
-		var val = Math.pow(2, level - 1)
+		val = Math.pow(2, level - 1);
 		rotateAndFlipQuadrant(val, point, rx, ry);
 
 		point.x += val * rx;
@@ -302,20 +304,19 @@ S2.S2Cell.FromHilbertQuadKey = function(hilbertQuadkey) {
 
 	}
 
-  if(face % 2 == 1)
-  {
+  if (face % 2 === 1) {
     var t = point.x;
     point.x = point.y;
     point.y = t;
   }
 
 
-  return S2.S2Cell.FromFaceIJ(parseInt(face),[point.x, point.y],level)
+  return S2.S2Cell.FromFaceIJ(parseInt(face), [point.x, point.y], level);
+};
 
-}
 //static method to construct
 S2.S2Cell.FromLatLng = function(latLng, level) {
-  if (latLng.lat == null ||  latLng.lng == null) {
+  if ((!latLng.lat && latLng.lat !== 0) || (!latLng.lng && latLng.lng !== 0)) {
     throw new Error("Pass { lat: lat, lng: lng } to S2.S2Cell.FromLatLng");
   }
   var xyz = S2.LatLngToXYZ(latLng);
@@ -327,6 +328,7 @@ S2.S2Cell.FromLatLng = function(latLng, level) {
 
   return S2.S2Cell.FromFaceIJ (faceuv[0], ij, level);
 };
+
 /*
 S2.faceIjLevelToXyz = function (face, ij, level) {
   var st = S2.IJToST(ij, level, [0.5, 0.5]);
@@ -517,8 +519,21 @@ S2.idToKey = S2.S2Cell.idToKey
   return faceS + '/' + posS;
 };
 
+S2.keyToLatLng = S2.S2Cell.keyToLatLng = function (key) {
+  var cell2 = S2.S2Cell.FromHilbertQuadKey(key);
+  return cell2.getLatLng();
+};
+
+S2.idToLatLng = S2.S2Cell.idToLatLng = function (id) {
+  var key = S2.idToKey(id);
+  return S2.keyToLatLng(key);
+};
+
 S2.S2Cell.latLngToKey = S2.latLngToKey
 = S2.latLngToQuadkey = function (lat, lng, level) {
+  if (isNaN(level) || level < 1 || level > 30) {
+    throw new Error("'level' is not a number between 1 and 30 (but it should be)");
+  }
   // TODO
   //
   // S2.idToLatLng(id)

tests/hilbert-to-cell.js

@@ -1,10 +1,8 @@
+'use strict';
+
 var S2 = require('../src/s2geometry.js').S2;
 
-
-
-
-for(var level = 1; level <= 20; level++)
-{
+for(var level = 1; level <= 20; level++) {
 	var success = 0;
 	var total = 0;
 	for (var x = -180.0; x < 180; x += 0.5) {
@@ -34,10 +32,5 @@ for(var level = 1; level <= 20; level++)
 		}
 	}
 
-	console.log("level:" + level + "\t total:" + total + "\t success:" + success)
+	console.log("level:" + level + "\t total:" + total + "\t success:" + success);
 }
-
-
-
-
-

tests/key-id-to-latlng.js

@@ -0,0 +1,48 @@
+'use strict';
+
+var S2 = require('../src/s2geometry.js').S2;
+var x, y;
+var count = 0;
+
+function refCheck() {
+  var refKey = '4/032212303102210';
+  var latlng = {
+    'lat': 40.2574448
+  , 'lng': -111.7089464
+  };
+
+  var key = S2.latLngToKey(latlng.lat, latlng.lng, 15);
+  if (key !== refKey) {
+    throw new Error("reference doesn't match");
+  }
+
+  var latlng1 = S2.keyToLatLng('4/032212303102210');
+  var key1 = S2.latLngToKey(latlng1.lat, latlng1.lng, 15);
+  if (key1 !== refKey) {
+    throw new Error("reference 1 doesn't match");
+  }
+
+  var latlng2 = S2.idToLatLng('9749618446378729472');
+  var key2 = S2.latLngToKey(latlng2.lat, latlng2.lng, 15);
+  if (key2 !== refKey) {
+    throw new Error("reference 2 doesn't match");
+  }
+}
+
+function checkReal(lat, lng) {
+  var key = S2.latLngToKey(lat, lng, 15);
+  var latlng = S2.keyToLatLng(key);
+  var key2 = S2.latLngToKey(latlng.lat, latlng.lng, 15);
+  if (key !== key2) {
+    throw new Error("keys do not match", latlng, key, key2);
+  }
+}
+
+for (x = -180; x <= 180; x += (0 + Math.random())) {
+  for (y = -180; y <= 180; y += (0 + Math.random())) {
+    count += 1;
+    checkReal(x, y);
+  }
+}
+
+console.log('PASS:', count, 'random locations without any key mismatches');