drop last point from polygon rings, close #35

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### master
 
 - **Breaking:** removed TopoJSON support. It will likely branch out into a separate repo/project.
+- **Breaking:** changed encoding to not include the closing point of a polygon ring.
 - Fixed a bug with encoding single-ring single-polygon multipolygon.
 
 ### 1.0.1 (Jan 13, 2015)

decode.js

@@ -80,7 +80,8 @@ function readCoords(geom, pbf, type) {
     if (type === 'Point') geom.coordinates = readPoint(pbf);
     else if (type === 'MultiPoint') geom.coordinates = readLine(pbf, true);
     else if (type === 'LineString') geom.coordinates = readLine(pbf);
-    else if (type === 'MultiLineString' || type === 'Polygon') geom.coordinates = readMultiLine(pbf);
+    else if (type === 'MultiLineString') geom.coordinates = readMultiLine(pbf);
+    else if (type === 'Polygon') geom.coordinates = readMultiLine(pbf, true);
     else if (type === 'MultiPolygon') geom.coordinates = readMultiPolygon(pbf);
 }
 
@@ -116,7 +117,7 @@ function readPoint(pbf) {
     return coords;
 }
 
-function readLinePart(pbf, end, len) {
+function readLinePart(pbf, end, len, closed) {
     var i = 0,
         coords = [],
         p, d;
@@ -133,33 +134,34 @@ function readLinePart(pbf, end, len) {
         coords.push(p);
         i++;
     }
+    if (closed) coords.push(coords[0]);
 
     return coords;
 }
 
-function readLine(pbf, isMultiPoint) {
-    return readLinePart(pbf, pbf.readVarint() + pbf.pos, null, isMultiPoint);
+function readLine(pbf) {
+    return readLinePart(pbf, pbf.readVarint() + pbf.pos);
 }
 
-function readMultiLine(pbf) {
+function readMultiLine(pbf, closed) {
     var end = pbf.readVarint() + pbf.pos;
-    if (!lengths) return [readLinePart(pbf, end)];
+    if (!lengths) return [readLinePart(pbf, end, null, closed)];
 
     var coords = [];
-    for (var i = 0; i < lengths.length; i++) coords.push(readLinePart(pbf, end, lengths[i]));
+    for (var i = 0; i < lengths.length; i++) coords.push(readLinePart(pbf, end, lengths[i], closed));
     lengths = null;
     return coords;
 }
 
 function readMultiPolygon(pbf) {
     var end = pbf.readVarint() + pbf.pos;
-    if (!lengths) return [[readLinePart(pbf, end)]];
+    if (!lengths) return [[readLinePart(pbf, end, null, true)]];
 
     var coords = [];
     var j = 1;
     for (var i = 0; i < lengths[0]; i++) {
         var rings = [];
-        for (var k = 0; k < lengths[j]; k++) rings.push(readLinePart(pbf, end, lengths[j + 1 + k]));
+        for (var k = 0; k < lengths[j]; k++) rings.push(readLinePart(pbf, end, lengths[j + 1 + k], true));
         j += lengths[j] + 1;
         coords.push(rings);
     }

encode.js

@@ -122,7 +122,8 @@ function writeGeometry(geom, pbf) {
     if (geom.type === 'Point') writePoint(coords, pbf);
     else if (geom.type === 'MultiPoint') writeLine(coords, pbf, true);
     else if (geom.type === 'LineString') writeLine(coords, pbf);
-    if (geom.type === 'MultiLineString' || geom.type === 'Polygon') writeMultiLine(coords, pbf);
+    else if (geom.type === 'MultiLineString') writeMultiLine(coords, pbf);
+    else if (geom.type === 'Polygon') writeMultiLine(coords, pbf, true);
     else if (geom.type === 'MultiPolygon') writeMultiPolygon(coords, pbf);
     else if (geom.type === 'GeometryCollection') {
         for (var i = 0; i < geom.geometries.length; i++) pbf.writeMessage(4, writeGeometry, geom.geometries[i]);
@@ -171,23 +172,23 @@ function writePoint(point, pbf) {
     pbf.writePackedSVarint(3, coords);
 }
 
-function writeLine(line, pbf, isMultiPoint) {
+function writeLine(line, pbf) {
     var coords = [];
-    populateLine(coords, line, isMultiPoint);
+    populateLine(coords, line);
     pbf.writePackedSVarint(3, coords);
 }
 
-function writeMultiLine(lines, pbf) {
+function writeMultiLine(lines, pbf, closed) {
     var len = lines.length,
         i;
     if (len !== 1) {
         var lengths = [];
-        for (i = 0; i < len; i++) lengths.push(lines[i].length);
+        for (i = 0; i < len; i++) lengths.push(lines[i].length - (closed ? 1 : 0));
         pbf.writePackedVarint(2, lengths);
         // TODO faster with custom writeMessage?
     }
     var coords = [];
-    for (i = 0; i < len; i++) populateLine(coords, lines[i]);
+    for (i = 0; i < len; i++) populateLine(coords, lines[i], closed);
     pbf.writePackedSVarint(3, coords);
 }
 
@@ -198,21 +199,22 @@ function writeMultiPolygon(polygons, pbf) {
         var lengths = [len];
         for (i = 0; i < len; i++) {
             lengths.push(polygons[i].length);
-            for (j = 0; j < polygons[i].length; j++) lengths.push(polygons[i][j].length);
+            for (j = 0; j < polygons[i].length; j++) lengths.push(polygons[i][j].length - 1);
         }
         pbf.writePackedVarint(2, lengths);
     }
 
     var coords = [];
     for (i = 0; i < len; i++) {
-        for (j = 0; j < polygons[i].length; j++) populateLine(coords, polygons[i][j]);
+        for (j = 0; j < polygons[i].length; j++) populateLine(coords, polygons[i][j], true);
     }
     pbf.writePackedSVarint(3, coords);
 }
 
-function populateLine(coords, line) {
-    var i, j;
-    for (i = 0; i < line.length; i++) {
+function populateLine(coords, line, closed) {
+    var i, j,
+        len = line.length - (closed ? 1 : 0);
+    for (i = 0; i < len; i++) {
         for (j = 0; j < dim; j++) coords.push(Math.round((line[i][j] - (i ? line[i - 1][j] : 0)) * e));
     }
 }

test/fixtures/precision.json

@@ -0,0 +1,18 @@
+{
+    "type": "FeatureCollection",
+    "features": [
+        {
+            "type": "Feature",
+            "geometry": {
+                "type": "Polygon",
+                "coordinates": [[
+                    [5425435.733081569895148, 2012689.63544030720368],
+                    [5425333.066045090556145, 2012658.8061882276088],
+                    [5425324.357915714383125, 2012693.518385621719062],
+                    [5425426.5193927353248, 2012720.238697179593146],
+                    [5425435.733081569895148, 2012689.63544030720368]
+                ]]
+            }
+        }
+    ]
+}

test/validate.test.js

@@ -15,6 +15,14 @@ for (var name in geojsonFixtures) {
 test('roundtrip custom properties', roundtripTest(getJSON('props.json')));
 test('roundtrip single-ring MultiPolygon', roundtripTest(getJSON('single-multipoly.json')));
 
+test('roundtrip valid closed polygon with high-precision coordinates', function (t) {
+    var geojson = getJSON('precision.json');
+    var pbf = new Pbf(geobuf.encode(geojson, new Pbf()));
+    var ring = geobuf.decode(pbf).features[0].geometry.coordinates[0];
+    t.same(ring[0], ring[4]);
+    t.end();
+});
+
 function roundtripTest(geojson) {
     return function (t) {
         t.same(geobuf.decode(new Pbf(geobuf.encode(geojson, new Pbf()))), geojson);