From 42da3f18dd43f2302de82ad8341f0bccfc225dc7 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Sun, 5 Nov 2017 13:44:51 -0700
Subject: [PATCH] Keep longitude between -180 and 180

---
 src/ol/proj.js                                |  8 +++++-
 .../ol/{proj/index.test.js => proj.test.js}   | 27 +++++++++++++++++--
 2 files changed, 32 insertions(+), 3 deletions(-)
 rename test/spec/ol/{proj/index.test.js => proj.test.js} (96%)

diff --git a/src/ol/proj.js b/src/ol/proj.js
index fe2c0c9765..bf5b0bb6ac 100644
--- a/src/ol/proj.js
+++ b/src/ol/proj.js
@@ -3,6 +3,7 @@ goog.provide('ol.proj');
 goog.require('ol');
 goog.require('ol.Sphere');
 goog.require('ol.extent');
+goog.require('ol.math');
 goog.require('ol.proj.EPSG3857');
 goog.require('ol.proj.EPSG4326');
 goog.require('ol.proj.Projection');
@@ -282,8 +283,13 @@ ol.proj.fromLonLat = function(coordinate, opt_projection) {
  * @api
  */
 ol.proj.toLonLat = function(coordinate, opt_projection) {
-  return ol.proj.transform(coordinate,
+  var lonLat = ol.proj.transform(coordinate,
       opt_projection !== undefined ? opt_projection : 'EPSG:3857', 'EPSG:4326');
+  var lon = lonLat[0];
+  if (lon < -180 || lon > 180) {
+    lonLat[0] = ol.math.modulo(lon + 180, 360) - 180;
+  }
+  return lonLat;
 };
 
 
diff --git a/test/spec/ol/proj/index.test.js b/test/spec/ol/proj.test.js
similarity index 96%
rename from test/spec/ol/proj/index.test.js
rename to test/spec/ol/proj.test.js
index 211d19149e..5e68cbb34f 100644
--- a/test/spec/ol/proj/index.test.js
+++ b/test/spec/ol/proj.test.js
@@ -1,6 +1,5 @@
-
-
 goog.require('ol.proj');
+goog.require('ol.proj.EPSG3857');
 goog.require('ol.proj.EPSG4326');
 goog.require('ol.proj.Projection');
 
@@ -12,6 +11,30 @@ describe('ol.proj', function() {
     ol.proj.addCommon();
   });
 
+  describe('toLonLat()', function() {
+    var cases = [{
+      from: [0, 0],
+      to: [0, 0]
+    }, {
+      from: [-12356463.478053365, 5700582.732404122],
+      to: [-111, 45.5]
+    }, {
+      from: [2 * ol.proj.EPSG3857.HALF_SIZE - 12356463.478053365, 5700582.732404122],
+      to: [-111, 45.5]
+    }, {
+      from: [-4 * ol.proj.EPSG3857.HALF_SIZE - 12356463.478053365, 5700582.732404122],
+      to: [-111, 45.5]
+    }];
+
+    cases.forEach(function(c) {
+      it('works for ' + c.from.join(', '), function() {
+        var lonLat = ol.proj.toLonLat(c.from);
+        expect(lonLat[0]).to.roughlyEqual(c.to[0], 1e-9);
+        expect(lonLat[1]).to.roughlyEqual(c.to[1], 1e-9);
+      });
+    });
+  });
+
   describe('projection equivalence', function() {
 
     function _testAllEquivalent(codes) {