Avoid error when there is no layer with a keyid

Fixes #2215

diff --git a/app/assets/javascripts/leaflet.map.js b/app/assets/javascripts/leaflet.map.js
index 0cee211..1f161ce 100644 (file)
--- a/app/assets/javascripts/leaflet.map.js
+++ b/app/assets/javascripts/leaflet.map.js
@@ -96,11 +96,11 @@ L.OSM.Map = L.Map.extend({
   },
 
   getMapBaseLayerId: function () {
-    var baseLayer;
+    var baseLayerId;
     this.eachLayer(function (layer) {
-      if (layer.options && layer.options.keyid) baseLayer = layer;
+      if (layer.options && layer.options.keyid) baseLayerId = layer.options.keyid;
     });
-    return baseLayer.options.keyid;
+    return baseLayerId;
   },
 
   getUrl: function (marker) {