diff --git a/src/services/featurehelper.js b/src/services/featurehelper.js
index 9a84f3e092a6..d526be45c3a8 100644
--- a/src/services/featurehelper.js
+++ b/src/services/featurehelper.js
@@ -503,6 +503,9 @@ ngeo.FeatureHelper.prototype.exportKML = function(features) {
 
 
 /**
+ * Export features using a given format to a specific filename and download
+ * the result to the browser. The projection of the exported features is:
+ * `EPSG:4326`.
  * @param {Array.<ol.Feature>} features Array of vector features.
  * @param {ol.format.Feature} format Format
  * @param {string} fileName Name of the file.