bugfix for accumulating rounding errors encoding

jieter · Nov 7, 2019 · b23d198 · b23d198
1 parent 68e7819
commit b23d198
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/Polyline.encoded.js b/Polyline.encoded.js
@@ -78,7 +78,7 @@
 
             for (var i = 0, len = numbers.length; i < len;) {
                 for (var d = 0; d < options.dimension; ++d, ++i) {
-                    var num = numbers[i];
+                    var num = numbers[i].toFixed(options.precision);
                     var delta = num - (lastNumbers[d] || 0);
                     lastNumbers[d] = num;
 

diff --git a/test/test.js b/test/test.js
@@ -8,7 +8,7 @@ require('chai-leaflet')
 chai.should();
 
 describe('PolyUtil', function () {
-    var latlngs, encoded, encoded6, encoded5, delta;
+    var latlngs, latlngs6, encoded, encoded6, encoded5, delta;
 
     var floats, smallFloats, encodedFloats;
     var signedIntegers, encodedSignedIntegers;
@@ -23,6 +23,16 @@ describe('PolyUtil', function () {
             [43.252, -126.453]
         ];
 
+        latlngs6 = [
+            [0.000000, 0.000000],
+            [0.000006, 0.000006],
+            [0.000012, 0.000012],
+            [0.000018, 0.000018],
+            [0.000024, 0.000024],
+            [0.000030, 0.000030],
+            [0.000000, 0.000000]
+        ];
+
         encoded = '_p~iF~cn~U_ulLn{vA_mqNvxq`@';
         encoded5 = 'ehukEveaqO|D~Laf@YiZw[oOgQqGeIqE_GeXu_@aOiKkCkMbGrDxIzF`Ct@~@L`FYhAMrNoFfEoArIwBvGwBvB}@jHcBnFcBz@g@jMsDzJ_DfEoAf@SRjCrDbQbBg@vB{@jCoArDg@bBfE|CvKtIbWrDrNvBnAvGfEvBjGqNzNcMtDgN`I_LpM';
         encoded6 = '_izlhA~pvydF_{geC~{mZ_kwzCn`{nI';
@@ -113,6 +123,11 @@ describe('PolyUtil', function () {
             polyUtil.decode(encoded).should.eql(latlngs);
         });
 
+        it('with precision 6 latlngs to catch accumulating rounding errors', function () {
+            var encoded = polyUtil.encode(latlngs6);
+            polyUtil.decode(encoded).pop().should.eql(latlngs6.pop());
+        });
+
         it('latlngs height', function () {
             var xyz = [
                 [38.5, -120.5, 3],