diff -r 4a04bb856ac7 -r 2dd083dded66 gui/mapstorage.cc
--- a/gui/mapstorage.cc	Tue Aug 23 07:36:09 2005 +0000
+++ b/gui/mapstorage.cc	Tue Aug 23 15:57:12 2005 +0000
@@ -11,6 +11,9 @@
 
   nodemap_storage["id"] = new Graph::NodeMap<double>(graph);
   edgemap_storage["id"] = new Graph::EdgeMap<double>(graph);
+
+  nodemap_default["id"] = 1.0;
+  edgemap_default["id"] = 1.0;
 }
 
 MapStorage::~MapStorage()
@@ -125,6 +128,7 @@
 {
   bool read_x = false;
   bool read_y = false;
+  bool read_edge_id = false;
 
   try {
     LemonReader lreader(filename);
@@ -182,6 +186,16 @@
     return 1;
   }
 
+  if (!read_edge_id)
+  {
+    edgemap_storage["id"] = new Graph::EdgeMap<double>(graph);
+    int i = 1;
+    for (EdgeIt e(graph); e != INVALID; ++e)
+    {
+      (*edgemap_storage["id"])[e] = i++;
+    }
+  }
+
   if (!read_x || !read_y)
   {
     int node_num = 0;
@@ -210,6 +224,17 @@
     {
       nodemap_default[it->first] = 0.0;
     }
+    else if (it->first == "id")
+    {
+      NodeIt n(graph);
+      double max = (*nodemap_storage["id"])[n];
+      for (; n != INVALID; ++n)
+      {
+        if ((*nodemap_storage["id"])[n] > max)
+          max = (*nodemap_storage["id"])[n];
+      }
+      nodemap_default["id"] = max + 1.0;
+    }
   }
   for (std::map<std::string, Graph::EdgeMap<double>*>::const_iterator it =
       edgemap_storage.begin(); it != edgemap_storage.end(); ++it)
@@ -218,6 +243,17 @@
     {
       edgemap_default[it->first] = 0.0;
     }
+    else
+    {
+      EdgeIt e(graph);
+      double max = (*edgemap_storage["id"])[e];
+      for (; e != INVALID; ++e)
+      {
+        if ((*edgemap_storage["id"])[e] > max)
+          max = (*edgemap_storage["id"])[e];
+      }
+      edgemap_default["id"] = max + 1.0;
+    }
   }
 
   return 0;
@@ -267,12 +303,14 @@
   for (std::map<std::string, double>::iterator it =
       nodemap_default.begin(); it != nodemap_default.end(); ++it)
   {
-    nodemap_default.erase(it);
+    if (it->first != "id")
+      nodemap_default.erase(it);
   }
   for (std::map<std::string, double>::iterator it =
       edgemap_default.begin(); it != edgemap_default.end(); ++it)
   {
-    edgemap_default.erase(it);
+    if (it->first != "id")
+      edgemap_default.erase(it);
   }
   graph.clear();
   file_name = "";