diff --git a/module/javascript/app/vmap/mapmanager/layerstree.js b/module/javascript/app/vmap/mapmanager/layerstree.js
index 1ec2f59db6427c0aeb5276b0c29a9a9190a9139b..9d87c7d5cd5609dc8e35f97159156492d1f21cf2 100644
--- a/module/javascript/app/vmap/mapmanager/layerstree.js
+++ b/module/javascript/app/vmap/mapmanager/layerstree.js
@@ -164,12 +164,14 @@ nsVmap.nsMapManager.LayersTree.prototype.LayertreeController = function ($scope,
     if (goog.isDefAndNotNull(oUrlParams['extent'])){
         oPositionOptions['extent'] = decodeURI(oUrlParams['extent']).split("|");
     }
-    if (goog.isDefAndNotNull(oUrlParams['lon']) &&
-        goog.isDefAndNotNull(oUrlParams['lat']) &&
-        goog.isDefAndNotNull(oUrlParams['zoom'])){
-        oPositionOptions['lon'] = decodeURI(oUrlParams['lon']);
-        oPositionOptions['lat'] = decodeURI(oUrlParams['lat']);
-        oPositionOptions['zoom'] = decodeURI(oUrlParams['zoom']);
+    if (goog.isDefAndNotNull(oUrlParams)) {
+        if (goog.isDefAndNotNull(oUrlParams['lon']) &&
+            goog.isDefAndNotNull(oUrlParams['lat']) &&
+            goog.isDefAndNotNull(oUrlParams['zoom'])){
+            oPositionOptions['lon'] = decodeURI(oUrlParams['lon']);
+            oPositionOptions['lat'] = decodeURI(oUrlParams['lat']);
+            oPositionOptions['zoom'] = decodeURI(oUrlParams['zoom']);
+        }
     }
 
     this.loadTree(oPositionOptions);
@@ -464,7 +466,7 @@ nsVmap.nsMapManager.LayersTree.prototype.LayertreeController.prototype.loadTree
     }
 
     // Va à la position fournie
-    if (goog.isDefAndNotNull(oPositionOptions)) {        
+    if (goog.isDefAndNotNull(oPositionOptions)) {
         if (goog.isDefAndNotNull(oPositionOptions['lon']) &&
             goog.isDefAndNotNull(oPositionOptions['lat']) &&
             goog.isDefAndNotNull(oPositionOptions['zoom'])){