diff --git a/HISTORY.md b/HISTORY.md
index 49e09d02..107647df 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -2,6 +2,13 @@
 http://visjs.org
 
 
+## not-yet-released, version 4.15.1
+
+### Graph2d
+
+- Fixed #1692: Error when y-axis values are equal.
+
+
 ## 2016-02-23, version 4.15.0
 
 ### Timeline
diff --git a/lib/timeline/component/DataScale.js b/lib/timeline/component/DataScale.js
index 5065f0e3..a87477fb 100644
--- a/lib/timeline/component/DataScale.js
+++ b/lib/timeline/component/DataScale.js
@@ -59,7 +59,9 @@ DataScale.prototype.determineScale = function () {
   var range = this._end - this._start;
   this.scale = this.containerHeight / range;
   var minimumStepValue = this.majorCharHeight / this.scale;
-  var orderOfMagnitude = Math.round(Math.log(range) / Math.LN10);
+  var orderOfMagnitude = (range > 0)
+      ? Math.round(Math.log(range) / Math.LN10)
+      : 0;
 
   this.minorStepIdx = -1;
   this.magnitudefactor = Math.pow(10, orderOfMagnitude);