rebrand

support converting from HilbertQuadkey to s2Cell.

LICENSE

@@ -1,7 +1,7 @@
 ISC License (ISC)
 
 Copyright (c) 2012-2016, Jon Atkins <github@jonatkins.com>
-Copyright (c) 2016, AJ ONeal <coolaj86@gmail.com>
+Copyright (c) 2016, AJ ONeal <aj@daplie.com>
 
 Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
 

README.md

@@ -1,31 +1,186 @@
 s2-geometry (JavaScript/ES5.1)
 ======================
 
-A pure JavaScript/ES5.1 port of Google/Niantic's S2 Geometry library (used by **Ingress**, **Pokemon GO**)
+| Sponsored by [ppl](https://ppl.family)
+
+A pure JavaScript/ES5.1 port of Google/Niantic's S2 Geometry library (as used by **Ingress**, **Pokemon GO**)
 
 Currently contains basic support for S2Cell
 
+<table>
+<tr>
+<td></td>
+<td>
+Face 2
+<br>
+Orientation A
+
+<a href="http://i.imgur.com/SODO4bT.jpg" target="_face2"><img src="http://i.imgur.com/SODO4bTt.jpg" title="Face 2" alt="Face 2"></a>
+
+<br>
+The North Pole<br>(and Canada / Europe)
+</td>
+<td></td>
+</tr>
+<tr>
+<td>
+Face 0
+<br>
+Orientation A
+
+<a href="http://i.imgur.com/dLI5Zd1.jpg" target="_face0"><img src="http://i.imgur.com/dLI5Zd1t.jpg" title="Face 0" alt="Face 0"></a>
+
+<br>
+Africa
+</td>
+<td>
+Face 1
+<br>
+Orientation D
+
+<a href="http://i.imgur.com/duTLDTV.jpg" target="_face1"><img src="http://i.imgur.com/duTLDTVt.jpg" title="Face 1" alt="Face 1"></a>
+
+<br>
+Asia
+</td>
+<td>
+Face 3
+<br>
+Orientation D
+
+<a href="http://i.imgur.com/6Ho35Tc.jpg" target="_face3"><img src="http://i.imgur.com/6Ho35Tct.jpg" title="Face 3" alt="Face 3"></a>
+
+<br>
+Nothing<br>(and Australia)
+</td>
+<td>
+Face 4
+<br>
+Orientation A
+
+<a href="http://i.imgur.com/3IBAfqj.jpg" target="_face4"><img src="http://i.imgur.com/3IBAfqjt.jpg" title="Face 4" alt="Face 4"></a>
+
+<br>
+The Americas<br>(and Provo, UT)
+</td>
+</tr>
+<tr>
+<td></td>
+<td></td>
+<td></td>
+<td>
+Face 5
+<br>
+Orientation D
+
+<a href="http://i.imgur.com/HZCBvgy.jpg" target="_face5"><img src="http://i.imgur.com/HZCBvgyt.jpg" title="Face 5" alt="Face 5"></a>
+
+<br>
+Antarctica
+</td>
+</tr>
+</table>
+
+Where is this being used?
+---------------------
+
+* [pokemap-webapp](https://github.com/Daplie/pokemap-webapp)
+* [node-pokemap](https://github.com/Daplie/node-pokemap)
+* [Pokemon-GO-node-api](https://github.com/Daplie/Pokemon-GO-node-api)
+
 Simple Examples
 ---------------
 
 ```javascript
+'use strict';
+
+var S2 = require('s2-geometry').S2;
+
+var lat = 40.2574448;
+var lng = -111.7089464;
 var level = 15;
-var latlng = { lat: 40.2574448, lng: -111.7089464 };
-var cell = S2.S2Cell.FromLatLng(latlng, level);
 
-cell.getNeighbors();  // [ cellLeft, cellDown, cellRight, cellUp ]
 
-cell.getLatLng();     // { lat: 40.2574448, lng: -111.7089464 }
+
+//
+// Convert from Lat / Lng
+//
+var key = S2.latLngToKey(lat, lng, level);
+// '4/032212303102210'
+
+
+
+//
+// Convert between Hilbert Curve Quadtree Key and S2 Cell Id
+//
+var id = S2.keyToId(key);
+// '9749618446378729472'
+
+var key = S2.idToKey(id);
+// '9749618446378729472'
+
+
+//
+// Convert between Quadkey and Id
+//
+var latlng = S2.keyToLatLng(key);
+var latlng = S2.idToLatLng(id);
+
+
+
+//
+// Neighbors
+//
+var neighbors = S2.latLngToNeighborKeys(lat, lng, level);
+// [ keyLeft, keyDown, keyRight, keyUp ]
+
+
+
+//
+// Previous, Next, and Step
+//
+var nextKey = S2.nextKey(key);
+var prevKey = S2.prevKey(key);
+
+var backTenKeys = S2.stepKey(key, -10);
 ```
 
-convert Cell Id to Quadkey
+Previous and Next
+-----------------
+
+You can get the previous and next S2CellId from any given Key:
+
+1. Convert from Lat/Lng to Key (Face and Hilbert Curve Quadtree)
+2. Get the Previous or Next Key
+3. Convert the Key to an Id (uint64 string)
+
+```javascript
+var key = S2.latLngToKey(40.2574448, -111.7089464, 15);   // '4/032212303102210'
+var id = S2.keyToId(key);                                 // '9749618446378729472'
+
+var nextKey = S2.nextKey(key);
+var nextId = S2.keyToId(nextKey);
+
+var prevKey = S2.prevKey(key);
+var prevId = S2.keyToId(prevKey);
+
+var backTenKeys = S2.stepKey(key, -10);
+
+// See it
+console.log(prevKey);                                 // '4/032212303102203'
+console.log(key);                                     // '4/032212303102210'
+console.log(nextKey);                                 // '4/032212303102211'
+console.log(nextId);
+```
+
+convert Cell Id to Hilbert Curve Quad Tree
 ------------------
 
 Convert from base 10 (decimal) `S2 Cell Id` to base 4 `quadkey` (aka hilbert curve quadtree id)
 
 Example '4/032212303102210' becomes '9749618446378729472'
 
-```
+```javascript
 'use strict';
 
 var quadkey = '4/032212303102210'
@@ -34,7 +189,7 @@ var face = parts[0];                  // 4
 var position = parts[1];              // '032212303102210';
 var level = '032212303102210'.length; // 15
 
-var cellId = S2.fromFacePosLevel(face, position, level);
+var cellId = S2.facePosLevelToId(face, position, level);
 
 console.log(cellId);
 ```
@@ -43,12 +198,21 @@ Convert from hilbert quadtree id to s2 cell id:
 
 Example '9749618446378729472' becomes '4/032212303102210'
 
-```
+```javascript
 'use strict';
 
 var cellId = '9749618446378729472';
 
-var hilbertQuadkey = S2.toHilbertQuadkey(cellId);
+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');
+```

bower.json

@@ -34,5 +34,6 @@
     "bower_components",
     "test",
     "tests"
-  ]
+  ],
+  "version": "1.2.9"
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "s2-geometry",
-  "version": "1.1.0",
+  "version": "1.2.10",
   "description": "A pure JavaScript/ES5.1 port of Google/Niantic's S2 Geometry library (used by Ingress, Pokemon GO)",
   "main": "src/s2geometry.js",
   "scripts": {
@@ -8,7 +8,7 @@
   },
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/coolaj86/s2-geometry-javascript.git"
+    "url": "git+https://git.coolaj86.com/coolaj86/s2-geometry.js.git"
   },
   "keywords": [
     "s2",
@@ -28,11 +28,11 @@
     "lng"
   ],
   "author": "AJ ONeal <coolaj86@gmail.com> (https://coolaj86.com/)",
-  "license": "ISC",
+  "license": "(MIT or Apache-2 or ISC)",
   "bugs": {
-    "url": "https://github.com/coolaj86/s2-geometry-javascript/issues"
+    "url": "https://git.coolaj86.com/coolaj86/s2-geometry.js/issues"
   },
-  "homepage": "https://github.com/coolaj86/s2-geometry-javascript#readme",
+  "homepage": "https://git.coolaj86.com/coolaj86/s2-geometry.js#readme",
   "dependencies": {
     "long": "^3.2.0"
   }

src/s2geometry.js

@@ -22,12 +22,54 @@
 // - i,j: they always use 30 bits, adjusting as needed. we use 0 to (1<<level)-1 instead
 //        (so GetSizeIJ for a cell is always 1)
 
-(function(exports) {
+(function (exports) {
 'use strict';
 
-var S2 = exports.S2 = {};
+var S2 = exports.S2 = { L: {} };
 
-var LatLngToXYZ = function(latLng) {
+S2.L.LatLng = function (/*Number*/ rawLat, /*Number*/ rawLng, /*Boolean*/ noWrap) {
+  var lat = parseFloat(rawLat, 10);
+  var lng = parseFloat(rawLng, 10);
+
+  if (isNaN(lat) || isNaN(lng)) {
+    throw new Error('Invalid LatLng object: (' + rawLat + ', ' + rawLng + ')');
+  }
+
+  if (noWrap !== true) {
+    lat = Math.max(Math.min(lat, 90), -90);                 // clamp latitude into -90..90
+    lng = (lng + 180) % 360 + ((lng < -180 || lng === 180) ? 180 : -180);   // wrap longtitude into -180..180
+  }
+
+  return { lat: lat, lng: lng };
+};
+
+S2.L.LatLng.DEG_TO_RAD = Math.PI / 180;
+S2.L.LatLng.RAD_TO_DEG = 180 / Math.PI;
+
+/*
+S2.LatLngToXYZ = function(latLng) {
+  // http://stackoverflow.com/questions/8981943/lat-long-to-x-y-z-position-in-js-not-working
+  var lat = latLng.lat;
+  var lon = latLng.lng;
+  var DEG_TO_RAD = Math.PI / 180.0;
+
+  var phi = lat * DEG_TO_RAD;
+  var theta = lon * DEG_TO_RAD;
+
+  var cosLat = Math.cos(phi);
+  var sinLat = Math.sin(phi);
+  var cosLon = Math.cos(theta);
+  var sinLon = Math.sin(theta);
+  var rad = 500.0;
+
+  return [
+    rad * cosLat * cosLon
+  , rad * cosLat * sinLon
+  , rad * sinLat
+  ];
+};
+*/
+S2.LatLngToXYZ = function(latLng) {
   var d2r = S2.L.LatLng.DEG_TO_RAD;
 
   var phi = latLng.lat*d2r;
@@ -38,7 +80,7 @@ var LatLngToXYZ = function(latLng) {
   return [Math.cos(theta)*cosphi, Math.sin(theta)*cosphi, Math.sin(phi)];
 };
 
-var XYZToLatLng = function(xyz) {
+S2.XYZToLatLng = function(xyz) {
   var r2d = S2.L.LatLng.RAD_TO_DEG;
 
   var lat = Math.atan2(xyz[2], Math.sqrt(xyz[0]*xyz[0]+xyz[1]*xyz[1]));
@@ -85,7 +127,7 @@ var faceXYZToUV = function(face,xyz) {
 
 
 
-var XYZToFaceUV = function(xyz) {
+S2.XYZToFaceUV = function(xyz) {
   var face = largestAbsComponent(xyz);
 
   if (xyz[face] < 0) {
@@ -97,7 +139,7 @@ var XYZToFaceUV = function(xyz) {
   return [face, uv];
 };
 
-var FaceUVToXYZ = function(face,uv) {
+S2.FaceUVToXYZ = function(face,uv) {
   var u = uv[0];
   var v = uv[1];
 
@@ -120,7 +162,7 @@ var singleSTtoUV = function(st) {
   }
 };
 
-var STToUV = function(st) {
+S2.STToUV = function(st) {
   return [singleSTtoUV(st[0]), singleSTtoUV(st[1])];
 };
 
@@ -132,12 +174,12 @@ var singleUVtoST = function(uv) {
     return 1 - 0.5 * Math.sqrt (1 - 3*uv);
   }
 };
-var UVToST = function(uv) {
+S2.UVToST = function(uv) {
   return [singleUVtoST(uv[0]), singleUVtoST(uv[1])];
 };
 
 
-var STToIJ = function(st,order) {
+S2.STToIJ = function(st,order) {
   var maxSize = (1<<order);
 
   var singleSTtoIJ = function(st) {
@@ -149,7 +191,7 @@ var STToIJ = function(st,order) {
 };
 
 
-var IJToST = function(ij,order,offsets) {
+S2.IJToST = function(ij,order,offsets) {
   var maxSize = (1<<order);
 
   return [
@@ -158,12 +200,36 @@ var IJToST = function(ij,order,offsets) {
   ];
 };
 
+
+
+var rotateAndFlipQuadrant = function(n, point, rx, ry)
+{
+	var newX, newY;
+	if(ry == 0)
+	{
+		if(rx == 1){
+			point.x = n - 1 - point.x;
+			point.y = n - 1 - point.y
+
+		}
+
+    var x = point.x;
+		point.x = point.y
+		point.y = x;
+	}
+
+}
+
+
+
+
+
 // hilbert space-filling curve
 // based on http://blog.notdot.net/2009/11/Damn-Cool-Algorithms-Spatial-indexing-with-Quadtrees-and-Hilbert-Curves
 // note: rather then calculating the final integer hilbert position, we just return the list of quads
 // this ensures no precision issues whth large orders (S3 cell IDs use up to 30), and is more
 // convenient for pulling out the individual bits as needed later
-var pointToHilbertQuadList = function(x,y,order) {
+var pointToHilbertQuadList = function(x,y,order,face) {
   var hilbertMap = {
     'a': [ [0,'d'], [1,'a'], [3,'b'], [2,'a'] ],
     'b': [ [2,'b'], [1,'b'], [3,'a'], [0,'c'] ],
@@ -171,7 +237,10 @@ var pointToHilbertQuadList = function(x,y,order) {
     'd': [ [0,'a'], [3,'c'], [1,'d'], [2,'d'] ]
   };
 
-  var currentSquare='a';
+  if ('number' !== typeof face) {
+    console.warn(new Error("called pointToHilbertQuadList without face value, defaulting to '0'").stack);
+  }
+  var currentSquare = (face % 2) ? 'd' : 'a';
   var positions = [];
 
   for (var i=order-1; i>=0; i--) {
@@ -191,26 +260,86 @@ var pointToHilbertQuadList = function(x,y,order) {
   return positions;
 };
 
-
-
-
 // S2Cell class
 
 S2.S2Cell = function(){};
 
+S2.S2Cell.FromHilbertQuadKey = function(hilbertQuadkey) {
+  var parts = hilbertQuadkey.split('/');
+  var face = parseInt(parts[0]);
+  var position = parts[1];
+  var maxLevel = position.length;
+  var point = {
+    x : 0,
+    y: 0
+  };
+  var i;
+  var level;
+  var bit;
+  var rx, ry;
+  var val;
+
+	for(i = maxLevel - 1; i >= 0; i--) {
+
+		level = maxLevel - i;
+		bit = position[i];
+		rx = 0;
+    ry = 0;
+		if (bit === '1') {
+			ry = 1;
+		}
+		else if (bit === '2') {
+			rx = 1;
+			ry = 1;
+		}
+		else if (bit === '3') {
+			rx = 1;
+		}
+
+		val = Math.pow(2, level - 1);
+		rotateAndFlipQuadrant(val, point, rx, ry);
+
+		point.x += val * rx;
+		point.y += val * ry;
+
+	}
+
+  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);
+};
+
 //static method to construct
-S2.S2Cell.FromLatLng = function(latLng,level) {
+S2.S2Cell.FromLatLng = function(latLng, level) {
+  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);
 
-  var xyz = LatLngToXYZ(latLng);
+  var faceuv = S2.XYZToFaceUV(xyz);
+  var st = S2.UVToST(faceuv[1]);
 
-  var faceuv = XYZToFaceUV(xyz);
-  var st = UVToST(faceuv[1]);
-
-  var ij = STToIJ(st,level);
+  var ij = S2.STToIJ(st,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]);
+  var uv = S2.STToUV(st);
+  var xyz = S2.FaceUVToXYZ(face, uv);
+
+  return S2.XYZToLatLng(xyz);
+  return xyz;
+};
+*/
+
 S2.S2Cell.FromFaceIJ = function(face,ij,level) {
   var cell = new S2.S2Cell();
   cell.face = face;
@@ -226,11 +355,11 @@ S2.S2Cell.prototype.toString = function() {
 };
 
 S2.S2Cell.prototype.getLatLng = function() {
-  var st = IJToST(this.ij,this.level, [0.5,0.5]);
-  var uv = STToUV(st);
-  var xyz = FaceUVToXYZ(this.face, uv);
+  var st = S2.IJToST(this.ij,this.level, [0.5,0.5]);
+  var uv = S2.STToUV(st);
+  var xyz = S2.FaceUVToXYZ(this.face, uv);
 
-  return XYZToLatLng(xyz);
+  return S2.XYZToLatLng(xyz);
 };
 
 S2.S2Cell.prototype.getCornerLatLngs = function() {
@@ -243,22 +372,32 @@ S2.S2Cell.prototype.getCornerLatLngs = function() {
   ];
 
   for (var i=0; i<4; i++) {
-    var st = IJToST(this.ij, this.level, offsets[i]);
-    var uv = STToUV(st);
-    var xyz = FaceUVToXYZ(this.face, uv);
+    var st = S2.IJToST(this.ij, this.level, offsets[i]);
+    var uv = S2.STToUV(st);
+    var xyz = S2.FaceUVToXYZ(this.face, uv);
 
-    result.push ( XYZToLatLng(xyz) );
+    result.push ( S2.XYZToLatLng(xyz) );
   }
   return result;
 };
 
 
-S2.S2Cell.prototype.getFaceAndQuads = function() {
-  var quads = pointToHilbertQuadList(this.ij[0], this.ij[1], this.level);
+S2.S2Cell.prototype.getFaceAndQuads = function () {
+  var quads = pointToHilbertQuadList(this.ij[0], this.ij[1], this.level, this.face);
 
   return [this.face,quads];
 };
+S2.S2Cell.prototype.toHilbertQuadkey = function () {
+  var quads = pointToHilbertQuadList(this.ij[0], this.ij[1], this.level, this.face);
 
+  return this.face.toString(10) + '/' + quads.join('');
+};
+
+S2.latLngToNeighborKeys = S2.S2Cell.latLngToNeighborKeys = function (lat, lng, level) {
+  return S2.S2Cell.FromLatLng({ lat: lat, lng: lng }, level).getNeighbors().map(function (cell) {
+    return cell.toHilbertQuadkey();
+  });
+};
 S2.S2Cell.prototype.getNeighbors = function() {
 
   var fromFaceIJWrap = function(face,ij,level) {
@@ -271,14 +410,14 @@ S2.S2Cell.prototype.getNeighbors = function() {
       // with the assumption that they're only a little past the borders we can just take the points as
       // just beyond the cube face, project to XYZ, then re-create FaceUV from the XYZ vector
 
-      var st = IJToST(ij,level,[0.5,0.5]);
-      var uv = STToUV(st);
-      var xyz = FaceUVToXYZ(face,uv);
-      var faceuv = XYZToFaceUV(xyz);
+      var st = S2.IJToST(ij,level,[0.5,0.5]);
+      var uv = S2.STToUV(st);
+      var xyz = S2.FaceUVToXYZ(face,uv);
+      var faceuv = S2.XYZToFaceUV(xyz);
       face = faceuv[0];
       uv = faceuv[1];
-      st = UVToST(uv);
-      ij = STToIJ(st,level);
+      st = S2.UVToST(uv);
+      ij = S2.STToIJ(st,level);
       return S2.S2Cell.FromFaceIJ (face, ij, level);
     }
   };
@@ -303,10 +442,13 @@ S2.S2Cell.prototype.getNeighbors = function() {
 //
 S2.FACE_BITS = 3;
 S2.MAX_LEVEL = 30;
-S2.POS_BITS = (2 * S2.MAX_LEVEL) + 1;
+S2.POS_BITS = (2 * S2.MAX_LEVEL) + 1; // 61 (60 bits of data, 1 bit lsb marker)
 
-S2.fromFacePosLevel = function (faceN, posS, levelN) {
+S2.facePosLevelToId = S2.S2Cell.facePosLevelToId = S2.fromFacePosLevel = function (faceN, posS, levelN) {
   var Long = exports.dcodeIO && exports.dcodeIO.Long || require('long');
+  var faceB;
+  var posB;
+  var bin;
 
   if (!levelN) {
     levelN = posS.length;
@@ -315,30 +457,56 @@ S2.fromFacePosLevel = function (faceN, posS, levelN) {
     posS = posS.substr(0, levelN);
   }
 
-  var posB = Long.fromString(posS, true, 4).toString(2);
+  // 3-bit face value
+  faceB = Long.fromString(faceN.toString(10), true, 10).toString(2);
+  while (faceB.length < S2.FACE_BITS) {
+    faceB = '0' + faceB;
+  }
+
+  // 60-bit position value
+  posB = Long.fromString(posS, true, 4).toString(2);
   while (posB.length < (2 * levelN)) {
     posB = '0' + posB;
   }
-  var bin = Long.fromString(faceN.toString(10), true, 10).toString(2);
-  bin += posB;
+
+  bin = faceB + posB;
+  // 1-bit lsb marker
   bin += '1';
+  // n-bit padding to 64-bits
   while (bin.length < (S2.FACE_BITS + S2.POS_BITS)) {
     bin += '0';
   }
 
-  return Long.fromString(bin, true, 2).toString();
+  return Long.fromString(bin, true, 2).toString(10);
 };
 
-S2.toHilbertQuadkey = function (idS) {
+S2.keyToId = S2.S2Cell.keyToId
+= S2.toId = S2.toCellId = S2.fromKey
+= function (key) {
+  var parts = key.split('/');
+
+  return S2.fromFacePosLevel(parts[0], parts[1], parts[1].length);
+};
+
+S2.idToKey = S2.S2Cell.idToKey
+= S2.S2Cell.toKey = S2.toKey
+= S2.fromId = S2.fromCellId
+= S2.S2Cell.toHilbertQuadkey  = S2.toHilbertQuadkey
+= function (idS) {
   var Long = exports.dcodeIO && exports.dcodeIO.Long || require('long');
   var bin = Long.fromString(idS, true, 10).toString(2);
-  var lsbIndex = bin.lastIndexOf('1');
 
+  while (bin.length < (S2.FACE_BITS + S2.POS_BITS)) {
+    bin = '0' + bin;
+  }
+
+  // MUST come AFTER binstr has been left-padded with '0's
+  var lsbIndex = bin.lastIndexOf('1');
   // substr(start, len)
-  // substring(start, end)
-  var faceB = bin.substr(0, 3);
+  // substring(start, end) // includes start, does not include end
+  var faceB = bin.substring(0, 3);
   // posB will always be a multiple of 2 (or it's invalid)
-  var posB = bin.substring(4, lsbIndex);
+  var posB = bin.substring(3, lsbIndex);
   var levelN = posB.length / 2;
 
   var faceS = Long.fromString(faceB, true, 2).toString(10);
@@ -351,37 +519,76 @@ S2.toHilbertQuadkey = function (idS) {
   return faceS + '/' + posS;
 };
 
-})('undefined' !== typeof window ? window : module.exports);
+S2.keyToLatLng = S2.S2Cell.keyToLatLng = function (key) {
+  var cell2 = S2.S2Cell.FromHilbertQuadKey(key);
+  return cell2.getLatLng();
+};
 
-(function (exports) {
-'use strict';
+S2.idToLatLng = S2.S2Cell.idToLatLng = function (id) {
+  var key = S2.idToKey(id);
+  return S2.keyToLatLng(key);
+};
 
-  // Adapted from Leafletjs https://searchcode.com/codesearch/view/42525008/
-
-  var L = {};
-  var S2 = exports.S2;
-
-  if (!exports.L) {
-    exports.L = L;
+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)");
   }
-  S2.L = L;
+  // TODO
+  //
+  // S2.idToLatLng(id)
+  // S2.keyToLatLng(key)
+  // S2.nextFace(key)     // prevent wrapping on nextKey
+  // S2.prevFace(key)     // prevent wrapping on prevKey
+  //
+  // .toKeyArray(id)  // face,quadtree
+  // .toKey(id)       // hilbert
+  // .toPoint(id)     // ij
+  // .toId(key)       // uint64 (as string)
+  // .toLong(key)     // long.js
+  // .toLatLng(id)    // object? or array?, or string (with comma)?
+  //
+  // maybe S2.HQ.x, S2.GPS.x, S2.CI.x?
+  return S2.S2Cell.FromLatLng({ lat: lat, lng: lng }, level).toHilbertQuadkey();
+};
 
-  L.LatLng = function (/*Number*/ rawLat, /*Number*/ rawLng, /*Boolean*/ noWrap) {
-    var lat = parseFloat(rawLat, 10);
-    var lng = parseFloat(rawLng, 10);
+S2.stepKey = function (key, num) {
+  var Long = exports.dcodeIO && exports.dcodeIO.Long || require('long');
+  var parts = key.split('/');
 
-    if (isNaN(lat) || isNaN(lng)) {
-      throw new Error('Invalid LatLng object: (' + rawLat + ', ' + rawLng + ')');
-    }
+  var faceS = parts[0];
+  var posS = parts[1];
+  var level = parts[1].length;
 
-    if (noWrap !== true) {
-      lat = Math.max(Math.min(lat, 90), -90);                 // clamp latitude into -90..90
-      lng = (lng + 180) % 360 + ((lng < -180 || lng === 180) ? 180 : -180);   // wrap longtitude into -180..180
-    }
+  var posL = Long.fromString(posS, true, 4);
+  // TODO handle wrapping (0 === pos + 1)
+  // (only on the 12 edges of the globe)
+  var otherL;
+  if (num > 0) {
+    otherL = posL.add(Math.abs(num));
+  }
+  else if (num < 0) {
+    otherL = posL.subtract(Math.abs(num));
+  }
+  var otherS = otherL.toString(4);
 
-    return { lat: lat, lng: lng };
-  };
+  if ('0' === otherS) {
+    console.warning(new Error("face/position wrapping is not yet supported"));
+  }
 
-  L.LatLng.DEG_TO_RAD = Math.PI / 180;
-  L.LatLng.RAD_TO_DEG = 180 / Math.PI;
-})('undefined' !== typeof window ? window : module.exports);
+  while (otherS.length < level) {
+    otherS = '0' + otherS;
+  }
+
+  return faceS + '/' + otherS;
+};
+
+S2.S2Cell.prevKey = S2.prevKey = function (key) {
+  return S2.stepKey(key, -1);
+};
+
+S2.S2Cell.nextKey = S2.nextKey = function (key) {
+  return S2.stepKey(key, 1);
+};
+
+})('undefined' !== typeof module ? module.exports : window);

tests/conversions.js

@@ -0,0 +1,84 @@
+'use strict';
+
+var Long = require('long');
+var s2node = require('s2geometry-node');
+var S2 = require('../src/s2geometry.js').S2;
+
+var tests = [
+  { 'name': 'Provo, UT'
+  , 'lat': 40.2574448
+  , 'lng': -111.7089464
+  , 'key': ''
+  , 'id': ''
+  }
+, { 'name': 'Startup Building'
+  , 'lat': 40.2262363
+  , 'lng': -111.6630927
+  , 'key': ''
+  , 'id': ''
+  }
+, { 'name': "Kyderman's"
+  , 'lat': 51.352085106718384 // 51.352085106718384
+  , 'lng': -2.9877930879592896 // -2.9877930879592896
+  , 'key': ''
+  , 'id': ''
+  }
+, { 'name': "Toeler's"
+  , 'lat': -43.525166 // -43.5261282
+  , 'lng': 172.655096 // 172.6561085
+  , 'key': ''
+  , 'id': ''
+  }
+/*
+, { 'name': ""
+  , 'lat': 0
+  , 'lng': 0
+  , 'key': ''
+  , 'id': ''
+  }
+*/
+];
+
+// get known-expected values
+tests.forEach(function (loc) {
+  var level = 15;
+  var s2nLatLng = new s2node.S2LatLng(loc.lat, loc.lng);
+  var s2nId = new s2node.S2CellId(s2nLatLng).parent(level);
+  var s2nCell = new s2node.S2Cell(s2nId);
+
+  loc.face = s2nCell.face();
+  loc.id = s2nId.id();
+  loc.key = s2nId.toString();
+  loc.lat = s2nId.toLatLng().toString().split(',')[0];
+  loc.lng = s2nId.toLatLng().toString().split(',')[1];
+  loc.level = s2nId.level(); // always 15
+  loc.point = s2nId.toPoint()// .toArray();
+
+  //console.log(JSON.stringify(loc, null, '  '));
+
+  var key = S2.latLngToQuadkey(loc.lat, loc.lng, level);
+  var id = S2.toId(key);
+  var key2 = S2.toKey(id);
+  var id2 = S2.toId(key2);
+
+  if (loc.key !== key || loc.id !== id) {
+    console.error("Error testing " + loc.name + " @ " + loc.lat + ',' + loc.lng);
+    console.error("Calculated/Expected:");
+    console.error(id, ':', loc.id);
+    console.error(key, " : ", loc.key);
+    console.error(loc.point.x(), loc.point.y(), loc.point.z());
+    console.error(Long.fromString(id, true, 10).toString(2));
+    console.error(Long.fromString(loc.id, true, 10).toString(2));
+
+    throw new Error('Test Failed');
+  }
+
+  if (loc.key !== key2 || loc.id !== id2) {
+    console.error("Error testing " + loc.name + " @ " + loc.lat + ',' + loc.lng);
+    console.error("Secondary Key / ID conversion failed: Calculated/Expected:");
+    console.error(id2, ':', loc.id);
+    console.error(key2, " : ", loc.key);
+
+    throw new Error('Test Failed');
+  }
+});

tests/debug.js

@@ -0,0 +1,79 @@
+'use strict';
+
+//var oS2 = require('./s2geometry.old.js').S2;
+var jS2 = require('../src/s2geometry.js').S2;
+var nS2 = require('s2geometry-node');
+
+var lat = -43.525166;
+var lng = 172.655096;
+//var id = '8678661352471920640';
+
+var tests = [
+  [ -13.846153846153854, -41.53846153846155 ]   // face 0
+, [ -13.846153846153854, 96.92307692307692 ]    // face 1
+, [ 41.53846153846153, -124.61538461538463 ]    // face 2
+, [ -152.30769230769232, 41.53846153846153 ]    // face 3
+, [ -152.30769230769232, 69.23076923076923 ]    // face 4
+, [ -124.61538461538463, -69.23076923076924 ]   // face 5
+];
+
+var tests = [
+  [ -3.9832738, 12.6825449,   'The Congo          (Africa)' ]
+, [ 19.0827696, 72.7407752,   'Mumbai, India      (Asia)' ]
+, [ 68.5207533, -74.9563282,  'Greenland          (North Pole)' ]
+, [ -1.573289, -158.957890,   'The Pacific Ocean  (nowhere)' ]
+, [ 40.2573137, -111.7091177, 'Provo, UT, USA     (Americas)' ]
+, [ -46.362972,-73.7431064,   'Antarctica         (South Pole)' ]
+];
+
+var bugReports = [
+  // https://github.com/jonatkins/s2-geometry-javascript/issues/12
+  [ -6.120097, 106.846511, '@Skeec' ]
+  // https://github.com/coolaj86/s2-geometry-javascript/issues/8#issuecomment-237204759
+, [ -33.87347601637759, 151.1954084522501 ]
+  // https://github.com/Daplie/s2-geometry.js/issues/1
+, [ 45.74528835847731, 12.5516625, '@vekexasia' ]
+];
+
+tests.concat(bugReports).forEach(function (pair, i) {
+  var lat = pair[0];
+  var lng = pair[1];
+  var comment = pair[2] && ('(' + pair[2] + ')') || '';
+
+  console.log('');
+  console.log('');
+
+  if (i < 6) {
+    console.log('FACE', i);
+  }
+  console.log('Lat/Lng', '=', lat + ',' + lng, comment);
+
+  //
+  // Lat / Lng to XYZ
+  //
+  var nS2LatLng = new nS2.S2LatLng(lat, lng).toPoint();
+  //var nXyz = [ nS2LatLng.x(), nS2LatLng.y(), nS2LatLng.z() ];
+  //var jXyz = jS2.LatLngToXYZ({ lat: lat, lng: lng });
+  /*
+  console.log('');
+  console.log('XYZ');
+  console.log('=', nXyz);
+  console.log('j', jXyz);
+  */
+
+
+  var nCell = new nS2.S2CellId(nS2LatLng).parent(15);
+  var jCell = jS2.S2Cell.FromLatLng({ lat: lat, lng: lng }, 15);
+  /*
+  console.log('');
+  console.log('F,IJ,L');
+  console.log('j', jCell.toString());
+  */
+
+  var nKey = nCell.toString();
+  var jQuad = jCell.getFaceAndQuads();
+  var jKey = jQuad[0] + '/' + jQuad[1].join('');
+  console.log('Quadkey');
+  console.log('=', nKey);
+  console.log('j', jKey, "(" + jS2.toId(jKey) + ")");
+});

tests/example.provo.txt

@@ -0,0 +1,21 @@
+-10 4 '9749618424903892992' '4/032212303102122' '40.253289,-111.712279' 15
+-9 4 '9749618427051376640' '4/032212303102123' '40.253874,-111.709298' 15
+-8 4 '9749618429198860288' '4/032212303102130' '40.254460,-111.706317' 15
+-7 4 '9749618431346343936' '4/032212303102131' '40.252022,-111.706317' 15
+-6 4 '9749618433493827584' '4/032212303102132' '40.252607,-111.703336' 15
+-5 4 '9749618435641311232' '4/032212303102133' '40.255045,-111.703336' 15
+-4 4 '9749618437788794880' '4/032212303102200' '40.257483,-111.703336' 15
+-3 4 '9749618439936278528' '4/032212303102201' '40.259920,-111.703336' 15
+-2 4 '9749618442083762176' '4/032212303102202' '40.259335,-111.706317' 15
+-1 4 '9749618444231245824' '4/032212303102203' '40.256897,-111.706317' 15
+0 4 '9749618446378729472' '4/032212303102210' '40.256312,-111.709298' 15
+1 4 '9749618448526213120' '4/032212303102211' '40.255727,-111.712279' 15
+2 4 '9749618450673696768' '4/032212303102212' '40.258165,-111.712279' 15
+3 4 '9749618452821180416' '4/032212303102213' '40.258750,-111.709298' 15
+4 4 '9749618454968664064' '4/032212303102220' '40.261188,-111.709298' 15
+5 4 '9749618457116147712' '4/032212303102221' '40.260602,-111.712279' 15
+6 4 '9749618459263631360' '4/032212303102222' '40.263040,-111.712279' 15
+7 4 '9749618461411115008' '4/032212303102223' '40.263625,-111.709298' 15
+8 4 '9749618463558598656' '4/032212303102230' '40.264210,-111.706317' 15
+9 4 '9749618465706082304' '4/032212303102231' '40.261773,-111.706317' 15
+10 4 '9749618467853565952' '4/032212303102232' '40.262358,-111.703336' 15

tests/example.startup.txt

@@ -0,0 +1,21 @@
+-10 4 '9749615149991329792' '4/032212302322211' '40.235133,-111.655639' 15
+-9 4 '9749615152138813440' '4/032212302322212' '40.234549,-111.658620' 15
+-8 4 '9749615154286297088' '4/032212302322213' '40.232110,-111.658620' 15
+-7 4 '9749615156433780736' '4/032212302322220' '40.231526,-111.661601' 15
+-6 4 '9749615158581264384' '4/032212302322221' '40.233965,-111.661601' 15
+-5 4 '9749615160728748032' '4/032212302322222' '40.233381,-111.664582' 15
+-4 4 '9749615162876231680' '4/032212302322223' '40.230942,-111.664582' 15
+-3 4 '9749615165023715328' '4/032212302322230' '40.228503,-111.664582' 15
+-2 4 '9749615167171198976' '4/032212302322231' '40.229087,-111.661601' 15
+-1 4 '9749615169318682624' '4/032212302322232' '40.226647,-111.661601' 15
+0 4 '9749615171466166272' '4/032212302322233' '40.226063,-111.664582' 15
+1 4 '9749615173613649920' '4/032212302322300' '40.223624,-111.664582' 15
+2 4 '9749615175761133568' '4/032212302322301' '40.221184,-111.664582' 15
+3 4 '9749615177908617216' '4/032212302322302' '40.221768,-111.661601' 15
+4 4 '9749615180056100864' '4/032212302322303' '40.224208,-111.661601' 15
+5 4 '9749615182203584512' '4/032212302322310' '40.224791,-111.658620' 15
+6 4 '9749615184351068160' '4/032212302322311' '40.225375,-111.655639' 15
+7 4 '9749615186498551808' '4/032212302322312' '40.222935,-111.655639' 15
+8 4 '9749615188646035456' '4/032212302322313' '40.222352,-111.658620' 15
+9 4 '9749615190793519104' '4/032212302322320' '40.219912,-111.658620' 15
+10 4 '9749615192941002752' '4/032212302322321' '40.220496,-111.655639' 15

tests/exhaustive.js

@@ -0,0 +1,32 @@
+'use strict';
+
+var jS2 = require('../src/s2geometry.js').S2;
+var nS2 = require('s2geometry-node');
+
+var x, y;
+
+function checkReal(lat, lng) {
+  var nS2LatLng = new nS2.S2LatLng(lat, lng).toPoint();
+  var nCell = new nS2.S2CellId(nS2LatLng).parent(15);
+  var jCell = jS2.S2Cell.FromLatLng({ lat: lat, lng: lng }, 15);
+  var nKey = nCell.toString();
+  var jQuad = jCell.getFaceAndQuads();
+  var jKey = jQuad[0] + '/' + jQuad[1].join('');
+
+  if (nKey !== jKey) {
+    console.log('');
+    console.log('Quadkey');
+    console.log('=', nKey);
+    console.log('j', jKey);
+    throw new Error("values didn't match expected");
+  }
+}
+
+console.log('Exhaustive check of about 518,400 random lat,lng coordinates of the earth (about every 0.5°)');
+console.log('(this will take several seconds)');
+for (x = -180; x <= 180; x += (0 + Math.random())) {
+  for (y = -180; y <= 180; y += (0 + Math.random())) {
+    checkReal(x, y);
+  }
+}
+console.log('PASS');

tests/hilbert-to-cell.js

@@ -0,0 +1,36 @@
+'use strict';
+
+var S2 = require('../src/s2geometry.js').S2;
+
+for(var level = 1; level <= 20; level++) {
+	var success = 0;
+	var total = 0;
+	for (var x = -180.0; x < 180; x += 0.5) {
+		for (var y = -180.0; y < 180; y += 0.5) {
+
+				var latlng = { lat: x, lng: y };
+				var cell = S2.S2Cell.FromLatLng(latlng, level);
+				var quadKey = cell.toHilbertQuadkey();
+				var cell2 = S2.S2Cell.FromHilbertQuadKey(quadKey);
+
+				if(cell.face != cell2.face ||
+					cell.ij[0] != cell2.ij[0] ||
+					cell.ij[1] != cell2.ij[1] ||
+					cell.level != cell2.level)
+					{
+						/*console.log({
+							cell: cell,
+							cell2: cell2})*/
+
+					}
+					else
+					{
+						success++;
+					}
+					total++;
+				// check equal
+		}
+	}
+
+	console.log("level:" + level + "\t total:" + total + "\t success:" + success);
+}

tests/js-vs-go.js

@@ -0,0 +1,33 @@
+'use strict';
+
+var tests = require('./generated-locations.json');
+var jS2 = require('../src/s2geometry.js').S2;
+
+function checkReal(loc) {
+  var jCell = jS2.S2Cell.FromLatLng({ lat: loc.lat, lng: loc.lng }, 15);
+  var jQuad = jCell.getFaceAndQuads();
+  var jKey = jQuad[0] + '/' + jQuad[1].join('');
+
+  if (loc.quadkey !== jKey) {
+    loc.badFace = jCell.face;
+    loc.badI = jCell.ij[0];
+    loc.badJ = jCell.ij[1];
+    loc.badQuad = jKey;
+    loc.badId = jS2.toId(jKey);
+    console.log(JSON.stringify(loc, null, '  ') + ',');
+    console.log('');
+    console.log('Lat/Lng:', loc.lat, loc.lng);
+    console.log('');
+    console.log('I, J:');
+    console.log('=', loc.i, loc.j);
+    console.log('j', jCell.ij.join(', '));
+    console.log('');
+    console.log('Quadkey');
+    console.log('=', loc.quadkey);
+    console.log('j', jKey);
+    throw new Error("values didn't match expected");
+  }
+}
+
+tests.forEach(checkReal);
+console.log('PASS');

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');

tests/latlng2cell.js

@@ -3,13 +3,37 @@
 var S2 = require('../src/s2geometry.js').S2;
 
 var level = 15;
-var latlng = { lat: 40.2574448, lng: -111.7089464 };
+
+// Provo, UT (Center St)
+// '9749618446378729472' '4/032212303102210' '40.256312,-111.709298' 15
+//                        4/032212303102210
+//var lat = 40.2574448;
+//var lng = -111.7089464;
+var latlng = { lat: 40.256312, lng: -111.709298 };
 var cell = S2.S2Cell.FromLatLng(latlng, level);
 
+console.log(cell.toHilbertQuadkey(), '4/032212303102210' === cell.toHilbertQuadkey());
+console.log(cell.getLatLng(), '40.256312,-111.709298' === cell.getLatLng(), '40.256312,-111.709298');
+
+// Startup Building in Provo
+// '9749615171466166272' '4/032212302322233' '40.226063,-111.664582' 15
+//                        4/032212302322233
+//var lat = 40.2262363;
+//var lng = -111.6630927;
+var latlng = { lat: 40.226063, lng: -111.664582 };
+var cell = S2.S2Cell.FromLatLng(latlng, level);
+
+console.log(cell.toHilbertQuadkey(), '4/032212302322233' === cell.toHilbertQuadkey());
+console.log(cell.getLatLng(), '40.226063,-111.664582' === cell.getLatLng(), '40.226063,-111.664582');
+
+/*
 cell.getNeighbors();  // [ cellLeft, cellDown, cellRight, cellUp ]
 
 latlng = cell.getLatLng();     // { lat: 40.2574448, lng: -111.7089464 }
 
+console.log(orig);
+console.log(latlng);
+
 if (40 === Math.round(latlng.lat) && -112 === Math.round(latlng.lng)) {
   console.log('OK');
   process.exit(0);
@@ -19,3 +43,4 @@ else {
   console.log(latlng);
   process.exit(1);
 }
+*/

tests/prev-next.js

@@ -0,0 +1,72 @@
+'use strict';
+
+var S2 = require('../src/s2geometry.js').S2;
+
+function getNeighbors(lat, lng, step) {
+    //var step = 10;
+    var level = 15;
+    var origin = S2.latLngToQuadkey(lat, lng, level);
+    var walk = [];
+    // 10 before and 10 after
+    var next = S2.nextKey(origin);
+    var prev = S2.prevKey(origin);
+    var i;
+
+    for (i = 0; i < step; i++) {
+        walk.unshift(S2.toId(prev));
+        prev = S2.prevKey(prev);
+    }
+
+    walk.push(S2.toId(origin));
+
+    for (i = 0; i < step; i++) {
+        // in range(10):
+        walk.push(S2.toId(next));
+        next = S2.nextKey(next);
+    }
+
+    return walk;
+}
+
+
+/*
+// Startup Building in Provo
+var lat = 40.2262363;
+var lng = -111.6630927;
+
+var walk = getNeighbors(lat, lng, 5);
+
+walk.forEach(function (cellId, i) {
+  var key = S2.fromId(cellId);
+  var face = parseInt(key.substr(0, 1), 10);
+  var pos = key.substr(2);
+  var level = pos.length;
+
+  // TODO
+  // S2.keyToLatLng(key);
+  // S2.idToLatLng(id);
+
+  // ! because converting CellId / HilbertQuadkey to LatLng is not implemented... yet
+  console.log(-((walk.length - 1) / 2) + i, face, cellId, S2.fromId(cellId), '!', level);
+});
+*/
+
+
+// Kyderman's test location
+var lat = 51.352085106718384;
+var lng = -2.9877930879592896;
+var walk = getNeighbors(lat, lng, 5);
+
+walk.forEach(function (cellId, i) {
+  var key = S2.fromId(cellId);
+  var face = parseInt(key.substr(0, 1), 10);
+  var pos = key.substr(2);
+  var level = pos.length;
+
+  // TODO
+  // S2.keyToLatLng(key);
+  // S2.idToLatLng(id);
+
+  // ! because converting CellId / HilbertQuadkey to LatLng is not implemented... yet
+  console.log(-((walk.length - 1) / 2) + i, face, cellId, S2.fromId(cellId), '!', level);
+});

tests/s2-node-hilbert.js

@@ -1,10 +1,23 @@
-var S2 = require('s2geometry-node');
-var lat = 40.2574448;
-var lng = -111.7089464;
+var s2n = require('s2geometry-node');
 
-var s2latlng = new S2.S2LatLng(lat, lng);
-var point;
-var cellId = new S2.S2CellId(s2latlng).parent(15);
+// Provo, UT (Center St)
+//var lat = 40.2574448;
+//var lng = -111.7089464;
+
+// Startup Building in Provo
+//var lat = 40.2262363;
+//var lng = -111.6630927;
+
+// Kyderman's test location
+//var lat = 51.352085106718384;
+//var lng = -2.9877930879592896;
+
+// Toeler's test location
+var lat = -43.5261282;
+var lng = 172.6561085;
+
+var s2nlatlng = new s2n.S2LatLng(lat, lng);
+var cellId = new s2n.S2CellId(s2nlatlng).parent(15);
 var cell;
 
 var walk = [];
@@ -34,6 +47,6 @@ walk.forEach(function (parts) {
   var i = parts[0];
   var cellId = parts[1];
 
-  cell = new S2.S2Cell(cellId);
+  cell = new s2n.S2Cell(cellId);
   console.log(i, cell.face(), cellId.id(), cellId.toString(), cellId.toLatLng().toString(), cellId.level());
 });

tests/simple.js

@@ -0,0 +1,51 @@
+'use strict';
+
+var S2 = require('../src/s2geometry.js').S2;
+
+var lat = 40.2574448;
+var lng = -111.7089464;
+var level = 15;
+
+
+
+//
+// Convert from Lat / Lng
+//
+var key = S2.latLngToKey(lat, lng, level);
+console.log(key);
+// '4/032212303102210'
+
+
+
+//
+// Convert between Hilbert Curve Quadtree Key and S2 Cell Id
+//
+var id = S2.keyToId(key);
+console.log(id);
+// '9749618446378729472'
+
+var key = S2.idToKey(id);
+console.log(key);
+// '9749618446378729472'
+
+
+
+//
+// Neighbors
+//
+var neighbors = S2.latLngToNeighborKeys(lat, lng, level);
+console.log(neighbors);
+// [ keyLeft, keyDown, keyRight, keyUp ]
+
+
+
+//
+// Previous, Next, and Step
+//
+var nextKey = S2.nextKey(key);
+console.log(nextKey);
+var prevKey = S2.prevKey(key);
+console.log(prevKey);
+
+var backTenKeys = S2.stepKey(key, -10);
+console.log(backTenKeys);