diff --git a/src/ol/geom/flatgeom.js b/src/ol/geom/flatgeom.js
index 3b080bf50a..df418f842a 100644
--- a/src/ol/geom/flatgeom.js
+++ b/src/ol/geom/flatgeom.js
@@ -148,6 +148,24 @@ ol.geom.flat.inflateCoordinatesss =
  * @param {number} offset Offset.
  * @param {number} end End.
  * @param {number} stride Stride.
+ * @return {number} Length.
+ */
+ol.geom.flat.lineStringLength = function(flatCoordinates, offset, end, stride) {
+  var x1 = flatCoordinates[offset];
+  var y1 = flatCoordinates[offset + 1];
+  var length = 0;
+  for (i = offset + stride; i < end; i += stride) {
+    var x2 = flatCoordinates[i];
+    var y2 = flatCoordinates[i + 1];
+    length += Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
+    x1 = x2;
+    y1 = y2;
+  }
+  return length;
+};
+
+
+/**
  * @param {number} x X.
  * @param {number} y Y.
  * @return {boolean} Contains (x, y).