diff --git a/externs/olx.js b/externs/olx.js
index 64f8fe9f5a..53744e0238 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -1932,7 +1932,7 @@ olx.format.TopoJSONOptions.prototype.defaultDataProjection;
 
 
 /**
- * @typedef {{altitudeMode: (ol.format.IGC.Z|undefined)}}
+ * @typedef {{altitudeMode: (ol.format.IGCZ|undefined)}}
  */
 olx.format.IGCOptions;
 
@@ -1940,7 +1940,7 @@ olx.format.IGCOptions;
 /**
  * Altitude mode. Possible values are `barometric`, `gps`, and `none`. Default
  * is `none`.
- * @type {ol.format.IGC.Z|undefined}
+ * @type {ol.format.IGCZ|undefined}
  * @api
  */
 olx.format.IGCOptions.prototype.altitudeMode;
diff --git a/src/ol/format/igc.js b/src/ol/format/igc.js
index ccfae500ba..38b949e0c5 100644
--- a/src/ol/format/igc.js
+++ b/src/ol/format/igc.js
@@ -3,6 +3,7 @@ goog.provide('ol.format.IGC');
 goog.require('ol');
 goog.require('ol.Feature');
 goog.require('ol.format.Feature');
+goog.require('ol.format.IGCZ');
 goog.require('ol.format.TextFeature');
 goog.require('ol.geom.GeometryLayout');
 goog.require('ol.geom.LineString');
@@ -31,10 +32,10 @@ ol.format.IGC = function(opt_options) {
 
   /**
    * @private
-   * @type {ol.format.IGC.Z}
+   * @type {ol.format.IGCZ}
    */
   this.altitudeMode_ = options.altitudeMode ?
-      options.altitudeMode : ol.format.IGC.Z.NONE;
+      options.altitudeMode : ol.format.IGCZ.NONE;
 
 };
 ol.inherits(ol.format.IGC, ol.format.TextFeature);
@@ -135,11 +136,11 @@ ol.format.IGC.prototype.readFeatureFromText = function(text, opt_options) {
           x = -x;
         }
         flatCoordinates.push(x, y);
-        if (altitudeMode != ol.format.IGC.Z.NONE) {
+        if (altitudeMode != ol.format.IGCZ.NONE) {
           var z;
-          if (altitudeMode == ol.format.IGC.Z.GPS) {
+          if (altitudeMode == ol.format.IGCZ.GPS) {
             z = parseInt(m[11], 10);
-          } else if (altitudeMode == ol.format.IGC.Z.BAROMETRIC) {
+          } else if (altitudeMode == ol.format.IGCZ.BAROMETRIC) {
             z = parseInt(m[12], 10);
           } else {
             ol.DEBUG && console.assert(false, 'Unknown altitude mode.');
@@ -173,7 +174,7 @@ ol.format.IGC.prototype.readFeatureFromText = function(text, opt_options) {
     return null;
   }
   var lineString = new ol.geom.LineString(null);
-  var layout = altitudeMode == ol.format.IGC.Z.NONE ?
+  var layout = altitudeMode == ol.format.IGCZ.NONE ?
       ol.geom.GeometryLayout.XYM : ol.geom.GeometryLayout.XYZM;
   lineString.setFlatCoordinates(layout, flatCoordinates);
   var feature = new ol.Feature(ol.format.Feature.transformWithOptions(
@@ -218,14 +219,3 @@ ol.format.IGC.prototype.readFeaturesFromText = function(text, opt_options) {
  * @api
  */
 ol.format.IGC.prototype.readProjection;
-
-
-/**
- * IGC altitude/z. One of 'barometric', 'gps', 'none'.
- * @enum {string}
- */
-ol.format.IGC.Z = {
-  BAROMETRIC: 'barometric',
-  GPS: 'gps',
-  NONE: 'none'
-};
diff --git a/src/ol/format/igcz.js b/src/ol/format/igcz.js
new file mode 100644
index 0000000000..3394a69945
--- /dev/null
+++ b/src/ol/format/igcz.js
@@ -0,0 +1,11 @@
+goog.provide('ol.format.IGCZ');
+
+/**
+ * IGC altitude/z. One of 'barometric', 'gps', 'none'.
+ * @enum {string}
+ */
+ol.format.IGCZ = {
+  BAROMETRIC: 'barometric',
+  GPS: 'gps',
+  NONE: 'none'
+};