map: various small fixes

lib/map.js

@@ -198,11 +198,6 @@ define(["map/clientlayer", "map/labelslayer",
           layerControl.addBaseLayer(layer, layerName)
           customLayers.add(layerName)
 
-          if (!layerControl.added) {
-            layerControl.addTo(map)
-            layerControl.added = true
-          }
-
           if (localStorageTest())
             localStorage.setItem("map/customLayers", JSON.stringify(Array.from(customLayers)))
         } catch (e) {
@@ -242,6 +237,7 @@ define(["map/clientlayer", "map/labelslayer",
       }))
 
       layerControl = L.control.layers(baseLayers, [], {position: "bottomright"})
+      layerControl.addTo(map)
 
       if (localStorageTest()) {
         var d = JSON.parse(localStorage.getItem("map/customLayers"))
@@ -277,6 +273,7 @@ define(["map/clientlayer", "map/labelslayer",
       }
 
       function resetZoom() {
+        if (barycenter)
           setView(barycenter.getBounds())
       }
 
@@ -321,6 +318,10 @@ define(["map/clientlayer", "map/labelslayer",
 
       function calcBarycenter(nodes) {
         nodes = nodes.map(function (d) { return d.nodeinfo.location })
+
+        if (nodes.length === 0)
+          return undefined
+
         var lats = nodes.map(function (d) { return d.latitude })
         var lngs = nodes.map(function (d) { return d.longitude })