diff --git a/src/Airports/xmlloader.cxx b/src/Airports/xmlloader.cxx
index dc24ec6c1..d5b90ad2f 100644
--- a/src/Airports/xmlloader.cxx
+++ b/src/Airports/xmlloader.cxx
@@ -75,15 +75,15 @@ bool XMLLoader::findAirportData(const std::string& aICAO,
     fileName.append(".xml");
   }
   
-  string_list sc = globals->get_fg_scenery();
+  PathList sc = globals->get_fg_scenery();
   char buffer[128];
   ::snprintf(buffer, 128, "%c/%c/%c/%s.%s", 
     aICAO[0], aICAO[1], aICAO[2], 
     aICAO.c_str(), fileName.c_str());
 
-  for (string_list_iterator it = sc.begin(); it != sc.end(); ++it) {
+    for (PathList::const_iterator it = sc.begin(); it != sc.end(); ++it) {
     // fg_senery contains empty strings as "markers" (see FGGlobals::set_fg_scenery)
-    if (!it->empty()) {
+    if (!it->isNull()) {
         SGPath path(*it);
         path.append("Airports");
         path.append(string(buffer));
diff --git a/src/GUI/AircraftModel.cxx b/src/GUI/AircraftModel.cxx
index 774608d1c..1bc27cb88 100644
--- a/src/GUI/AircraftModel.cxx
+++ b/src/GUI/AircraftModel.cxx
@@ -516,8 +516,8 @@ void AircraftItemModel::scanDirs()
 
     QStringList dirs = m_paths;
 
-    Q_FOREACH(std::string ap, globals->get_aircraft_paths()) {
-        dirs << QString::fromStdString(ap);
+    Q_FOREACH(SGPath ap, globals->get_aircraft_paths()) {
+        dirs << QString::fromStdString(ap.utf8Str());
     }
 
     SGPath rootAircraft(globals->get_fg_root());
diff --git a/src/GUI/CocoaHelpers.mm b/src/GUI/CocoaHelpers.mm
index 126b17c21..f93ff1edc 100644
--- a/src/GUI/CocoaHelpers.mm
+++ b/src/GUI/CocoaHelpers.mm
@@ -133,14 +133,14 @@ SGPath platformDefaultDataPath()
 namespace flightgear
 {
     
-std::string Options::platformDefaultRoot() const
+SGPath Options::platformDefaultRoot() const
 {
     CocoaAutoreleasePool ap;
     
     NSURL* url = [[NSBundle mainBundle] resourceURL];
     SGPath dataDir(URLToPath(url));
     dataDir.append("data");
-    return dataDir.str();
+    return dataDir;
 }
     
 } // of namespace flightgear
diff --git a/src/GUI/FGFontCache.cxx b/src/GUI/FGFontCache.cxx
index e5a0752a3..6d42e1c5c 100644
--- a/src/GUI/FGFontCache.cxx
+++ b/src/GUI/FGFontCache.cxx
@@ -177,9 +177,9 @@ void FGFontCache::init()
     if (!_initialized) {
         char *envp = ::getenv("FG_FONTS");
         if (envp != NULL) {
-            _path.set(envp);
+            _path = SGPath::fromEnv("FG_FONTS");
         } else {
-            _path.set(globals->get_fg_root());
+            _path = globals->get_fg_root();
             _path.append("Fonts");
         }
         _initialized = true;
diff --git a/src/GUI/QtLauncher.cxx b/src/GUI/QtLauncher.cxx
index f407f43fc..ed99bfa6f 100644
--- a/src/GUI/QtLauncher.cxx
+++ b/src/GUI/QtLauncher.cxx
@@ -386,7 +386,7 @@ void initApp(int& argc, char** argv)
 
         QSettings::setDefaultFormat(QSettings::IniFormat);
         QSettings::setPath(QSettings::IniFormat, QSettings::UserScope,
-                           QString::fromStdString(globals->get_fg_home()));
+                           QString::fromStdString(globals->get_fg_home().utf8Str()));
 
         // reset numeric / collation locales as described at:
         // http://doc.qt.io/qt-5/qcoreapplication.html#details
@@ -655,7 +655,7 @@ void QtLauncher::setSceneryPaths()
     SGPath terraSyncDir(downloadDir.toStdString());
     terraSyncDir.append("TerraSync");
     if (terraSyncDir.exists()) {
-        globals->append_fg_scenery(terraSyncDir.utf8Str());
+        globals->append_fg_scenery(terraSyncDir);
     }
 
 }
diff --git a/src/GUI/SetupRootDialog.cxx b/src/GUI/SetupRootDialog.cxx
index c0db35804..46c9f476c 100644
--- a/src/GUI/SetupRootDialog.cxx
+++ b/src/GUI/SetupRootDialog.cxx
@@ -90,7 +90,7 @@ bool SetupRootDialog::runDialog(PromptState prompt)
     return true;
 }
 
-std::string SetupRootDialog::restoreUserSelectedRoot()
+SGPath SetupRootDialog::restoreUserSelectedRoot()
 {
     QSettings settings;
     QString path = settings.value("fg-root").toString();
@@ -153,8 +153,8 @@ bool SetupRootDialog::validateVersion(QString path)
 
 bool SetupRootDialog::defaultRootAcceptable()
 {
-    std::string r = flightgear::Options::sharedInstance()->platformDefaultRoot();
-    QString defaultRoot = QString::fromStdString(r);
+    SGPath r = flightgear::Options::sharedInstance()->platformDefaultRoot();
+    QString defaultRoot = QString::fromStdString(r.utf8Str());
     return validatePath(defaultRoot) && validateVersion(defaultRoot);
 }
 
@@ -200,8 +200,8 @@ void SetupRootDialog::onDownload()
 
 void SetupRootDialog::onUseDefaults()
 {
-    std::string r = flightgear::Options::sharedInstance()->platformDefaultRoot();
-    m_browsedPath = QString::fromStdString(r);
+    SGPath r = flightgear::Options::sharedInstance()->platformDefaultRoot();
+    m_browsedPath = QString::fromStdString(r.utf8Str());
     globals->set_fg_root(r);
     QSettings settings;
     settings.remove("fg-root"); // remove any setting
@@ -211,7 +211,7 @@ void SetupRootDialog::onUseDefaults()
 void SetupRootDialog::updatePromptText()
 {
     QString t;
-    QString curRoot = QString::fromStdString(globals->get_fg_root());
+    QString curRoot = QString::fromStdString(globals->get_fg_root().utf8Str());
     switch (m_promptState) {
     case DefaultPathCheckFailed:
         t = tr("This copy of FlightGear does not include the base data files. " \
diff --git a/src/GUI/SetupRootDialog.hxx b/src/GUI/SetupRootDialog.hxx
index 2a1d4eae3..d294c1938 100644
--- a/src/GUI/SetupRootDialog.hxx
+++ b/src/GUI/SetupRootDialog.hxx
@@ -24,6 +24,8 @@
 
 #include <string>
 
+#include <simgear/misc/sg_path.hxx>
+
 namespace Ui
 {
     class SetupRootDialog;
@@ -38,7 +40,7 @@ public:
 
     static bool runDialog(bool usingDefaultRoot);
 
-    static std::string restoreUserSelectedRoot();
+    static SGPath restoreUserSelectedRoot();
 private slots:
 
     void onBrowse();
diff --git a/src/GUI/gui_funcs.cxx b/src/GUI/gui_funcs.cxx
index ce3c79eb0..7b4922dae 100644
--- a/src/GUI/gui_funcs.cxx
+++ b/src/GUI/gui_funcs.cxx
@@ -439,7 +439,7 @@ namespace
 {
     using namespace flightgear;
 
-    SGPath nextScreenshotPath(const std::string& screenshotDir)
+    SGPath nextScreenshotPath(const SGPath& screenshotDir)
     {
         char filename[32];
         static int count = 1;
@@ -497,12 +497,11 @@ namespace
 
             fgSetMouseCursor(MOUSE_CURSOR_NONE);
 
-            string dir = fgGetString("/sim/paths/screenshot-dir");
-            if (dir.empty())
-                dir = SGPath::desktop().str();
+            SGPath dir = SGPath::fromUtf8(fgGetString("/sim/paths/screenshot-dir"));
+            if (dir.isNull())
+                dir = SGPath::desktop();
 
-            _path.set(dir + '/');
-            if (_path.create_dir( 0755 )) {
+            if (!dir.exists() && dir.create_dir( 0755 )) {
                 SG_LOG(SG_GENERAL, SG_ALERT, "Cannot create screenshot directory '"
                         << dir << "'. Trying home directory.");
                 dir = globals->get_fg_home();
diff --git a/src/Main/AircraftDirVisitorBase.hxx b/src/Main/AircraftDirVisitorBase.hxx
index 78e7c90b8..7705dbdf2 100644
--- a/src/Main/AircraftDirVisitorBase.hxx
+++ b/src/Main/AircraftDirVisitorBase.hxx
@@ -43,11 +43,10 @@ protected:
     
     VisitResult visitAircraftPaths()
     {
-        const string_list& paths(globals->get_aircraft_paths());
-        string_list::const_iterator it = paths.begin();
+        const PathList& paths(globals->get_aircraft_paths());
+        PathList::const_iterator it = paths.begin();
         for (; it != paths.end(); ++it) {
-            SGPath p(*it);
-            VisitResult vr = visitDir(p, 0);
+            VisitResult vr = visitDir(*it, 0);
             if (vr != VISIT_CONTINUE) {
                 return vr;
             }
diff --git a/src/Main/fg_commands.cxx b/src/Main/fg_commands.cxx
index 98ea4b67c..8bce2f2be 100644
--- a/src/Main/fg_commands.cxx
+++ b/src/Main/fg_commands.cxx
@@ -538,7 +538,7 @@ do_materials_reload (const SGPropertyNode * arg)
     SGMaterialLib* new_matlib =  new SGMaterialLib;
     SGPath mpath( globals->get_fg_root() );
     mpath.append( fgGetString("/sim/rendering/materials-file") );
-    bool loaded = new_matlib->load(globals->get_fg_root(), 
+    bool loaded = new_matlib->load(globals->get_fg_root().local8BitStr(),
                                   mpath.str(), 
                                   globals->get_props());
 
diff --git a/src/Main/fg_init.cxx b/src/Main/fg_init.cxx
index 8b724d134..d95c80cab 100644
--- a/src/Main/fg_init.cxx
+++ b/src/Main/fg_init.cxx
@@ -172,7 +172,7 @@ string fgBasePackageVersion(const SGPath& base_path) {
         return string();
     }
     
-    sg_gzifstream in( p.str() );
+    sg_gzifstream in( p );
     if (!in.is_open()) {
         return string();
     }
@@ -277,27 +277,18 @@ public:
   }
   
 private:
-  SGPath getAircraftPaths() {
-    string_list pathList = globals->get_aircraft_paths();
-    SGPath aircraftPaths;
-    string_list::const_iterator it = pathList.begin();
-    if (it != pathList.end()) {
-        aircraftPaths.set(*it);
-        it++;
+    std::string getAircraftPaths()
+    {
+        return SGPath::join(globals->get_aircraft_paths(), ";");
     }
-    for (; it != pathList.end(); ++it) {
-        aircraftPaths.add(*it);
-    }
-    return aircraftPaths;
-  }
   
   bool checkCache()
   {
-    if (globals->get_fg_root() != _cache->getStringValue("fg-root", "")) {
+    if (globals->get_fg_root().utf8Str() != _cache->getStringValue("fg-root", "")) {
       return false; // cache mismatch
     }
 
-    if (getAircraftPaths().str() != _cache->getStringValue("fg-aircraft", "")) {
+    if (getAircraftPaths() != _cache->getStringValue("fg-aircraft", "")) {
       return false; // cache mismatch
     }
     
@@ -377,7 +368,7 @@ static SGPath platformDefaultDataPath()
 bool fgInitHome()
 {
   SGPath dataPath = SGPath::fromEnv("FG_HOME", platformDefaultDataPath());
-  globals->set_fg_home(dataPath.c_str());
+  globals->set_fg_home(dataPath);
     
     simgear::Dir fgHome(dataPath);
     if (!fgHome.exists()) {
@@ -387,7 +378,7 @@ bool fgInitHome()
     if (!fgHome.exists()) {
         flightgear::fatalMessageBox("Problem setting up user data",
                                     "Unable to create the user-data storage folder at: '"
-                                    + dataPath.str() + "'");
+                                    + dataPath.utf8Str() + "'");
         return false;
     }
     
@@ -503,13 +494,12 @@ static void initAircraftDirsNasalSecurity()
     sim->removeChildren("fg-aircraft");
 
     int index = 0;
-    string_list const aircraft_paths = globals->get_aircraft_paths();
-    for( string_list::const_iterator it = aircraft_paths.begin();
-                                     it != aircraft_paths.end();
-                                   ++it, ++index )
+    const PathList& aircraft_paths = globals->get_aircraft_paths();
+    for (PathList::const_iterator it = aircraft_paths.begin();
+         it != aircraft_paths.end(); ++it, ++index )
     {
         SGPropertyNode* n = sim->getChild("fg-aircraft", index, true);
-        n->setStringValue(*it);
+        n->setStringValue(it->utf8Str());
         n->setAttribute(SGPropertyNode::WRITE, false);
     }
 }
@@ -638,20 +628,18 @@ fgInitNav ()
 
 // General house keeping initializations
 bool fgInitGeneral() {
-    string root;
 
     SG_LOG( SG_GENERAL, SG_INFO, "General Initialization" );
     SG_LOG( SG_GENERAL, SG_INFO, "======= ==============" );
 
-    root = globals->get_fg_root();
-    if ( ! root.length() ) {
+    if ( globals->get_fg_root().isNull() ) {
         // No root path set? Then bail ...
         SG_LOG( SG_GENERAL, SG_ALERT,
                 "Cannot continue without a path to the base package "
                 << "being defined." );
         return false;
     }
-    SG_LOG( SG_GENERAL, SG_INFO, "FG_ROOT = " << '"' << root << '"' << endl );
+    SG_LOG( SG_GENERAL, SG_INFO, "FG_ROOT = " << '"' << globals->get_fg_root() << '"' << endl );
 
     // Note: browser command is hard-coded for Mac/Windows, so this only affects other platforms
     globals->set_browser(fgGetString("/sim/startup/browser-app", WEB_BROWSER));
@@ -683,8 +671,8 @@ void fgOutputSettings()
     SG_LOG( SG_GENERAL, SG_INFO, "download-dir = " << '"' << fgGetString("/sim/paths/download-dir") << '"' );
     SG_LOG( SG_GENERAL, SG_INFO, "terrasync-dir = " << '"' << fgGetString("/sim/terrasync/scenery-dir") << '"' );
 
-    SG_LOG( SG_GENERAL, SG_INFO, "aircraft-search-paths = \n\t" << simgear::strutils::join(globals->get_aircraft_paths(), "\n\t") );
-    SG_LOG( SG_GENERAL, SG_INFO, "scenery-search-paths = \n\t" << simgear::strutils::join(globals->get_fg_scenery(), "\n\t") );
+    SG_LOG( SG_GENERAL, SG_INFO, "aircraft-search-paths = \n\t" << SGPath::join(globals->get_aircraft_paths(), "\n\t") );
+    SG_LOG( SG_GENERAL, SG_INFO, "scenery-search-paths = \n\t" << SGPath::join(globals->get_fg_scenery(), "\n\t") );
 }
 
 // This is the top level init routine which calls all the other
@@ -743,7 +731,7 @@ void fgCreateSubsystems(bool duringReset) {
 
     SGPath mpath( globals->get_fg_root() );
     mpath.append( fgGetString("/sim/rendering/materials-file") );
-    if ( ! globals->get_matlib()->load(globals->get_fg_root(), mpath.str(),
+    if ( ! globals->get_matlib()->load(globals->get_fg_root().local8BitStr(), mpath.str(),
             globals->get_props()) ) {
        throw sg_io_exception("Error loading materials file", mpath);
     }
diff --git a/src/Main/globals.cxx b/src/Main/globals.cxx
index 796b18cd8..5a51cbc0d 100644
--- a/src/Main/globals.cxx
+++ b/src/Main/globals.cxx
@@ -108,10 +108,11 @@ public:
 
   // try each aircraft dir in turn
     std::string res(aResource, 9); // resource path with 'Aircraft/' removed
-    const string_list& dirs(globals->get_aircraft_paths());
-    string_list::const_iterator it = dirs.begin();
+    const PathList& dirs(globals->get_aircraft_paths());
+    PathList::const_iterator it = dirs.begin();
     for (; it != dirs.end(); ++it) {
-      SGPath p(*it, res);
+        SGPath p(*it);
+        p.append(res);
       if (p.exists()) {
         return p;
       }
@@ -131,8 +132,7 @@ public:
 
   virtual SGPath resolve(const std::string& aResource, SGPath&) const
   {
-    const char* aircraftDir = fgGetString("/sim/aircraft-dir");
-    SGPath p(aircraftDir);
+      SGPath p = SGPath::fromUtf8(fgGetString("/sim/aircraft-dir"));
     p.append(aResource);
     return p.exists() ? p : SGPath();
   }
@@ -248,7 +248,7 @@ FGGlobals::~FGGlobals()
 }
 
 // set the fg_root path
-void FGGlobals::set_fg_root (const std::string &root) {
+void FGGlobals::set_fg_root (const SGPath &root) {
     SGPath tmp(root);
     fg_root = tmp.realpath();
 
@@ -256,9 +256,9 @@ void FGGlobals::set_fg_root (const std::string &root) {
     tmp.append( "data" );
     tmp.append( "version" );
     if ( tmp.exists() ) {
-        fgGetNode("BAD_FG_ROOT", true)->setStringValue(fg_root);
-        fg_root += "/data";
-        fgGetNode("GOOD_FG_ROOT", true)->setStringValue(fg_root);
+        fgGetNode("BAD_FG_ROOT", true)->setStringValue(fg_root.utf8Str());
+        fg_root.append("data");
+        fgGetNode("GOOD_FG_ROOT", true)->setStringValue(fg_root.utf8Str());
         SG_LOG(SG_GENERAL, SG_ALERT, "***\n***\n*** Warning: changing bad FG_ROOT/--fg-root to '"
                 << fg_root << "'\n***\n***");
     }
@@ -268,7 +268,7 @@ void FGGlobals::set_fg_root (const std::string &root) {
     SGPropertyNode *n = fgGetNode("/sim", true);
     n->removeChild("fg-root", 0);
     n = n->getChild("fg-root", 0, true);
-    n->setStringValue(fg_root.c_str());
+    n->setStringValue(fg_root.utf8Str());
     n->setAttribute(SGPropertyNode::WRITE, false);
 
     simgear::ResourceManager::instance()->addBasePath(fg_root,
@@ -276,15 +276,15 @@ void FGGlobals::set_fg_root (const std::string &root) {
 }
 
 // set the fg_home path
-void FGGlobals::set_fg_home (const std::string &home) {
-    SGPath tmp(home);
-    fg_home = tmp.realpath();
+void FGGlobals::set_fg_home (const SGPath &home)
+{
+    fg_home = home.realpath();
 }
 
 PathList FGGlobals::get_data_paths() const
 {
     PathList r(additional_data_paths);
-    r.push_back(SGPath(fg_root));
+    r.push_back(fg_root);
     return r;
 }
 
@@ -329,69 +329,74 @@ SGPath FGGlobals::find_data_dir(const std::string& pathSuffix) const
     return SGPath();
 }
 
-void FGGlobals::append_fg_scenery (const std::string &paths, bool secure)
+void FGGlobals::append_fg_scenery (const PathList &paths, bool secure)
+{
+    BOOST_FOREACH(const SGPath& path, paths) {
+        append_fg_scenery(path);
+    }
+}
+
+void FGGlobals::append_fg_scenery (const SGPath &path, bool secure)
 {
     SGPropertyNode* sim = fgGetNode("/sim", true);
 
-  // find first unused fg-scenery property in /sim
+    // find first unused fg-scenery property in /sim
     int propIndex = 0;
     while (sim->getChild("fg-scenery", propIndex) != NULL) {
-      ++propIndex;
+        ++propIndex;
     }
 
-    BOOST_FOREACH(const SGPath& path, sgPathSplit( paths )) {
-        SGPath abspath(path.realpath());
-        if (!abspath.exists()) {
-          SG_LOG(SG_GENERAL, SG_WARN, "scenery path not found:" << abspath.str());
-          continue;
-        }
+    SGPath abspath(path.realpath());
+    if (!abspath.exists()) {
+        SG_LOG(SG_GENERAL, SG_WARN, "scenery path not found:" << abspath);
+        return;
+    }
 
-      // check for duplicates
-      string_list::const_iterator ex = std::find(fg_scenery.begin(), fg_scenery.end(), abspath.str());
-      if (ex != fg_scenery.end()) {
-        SG_LOG(SG_GENERAL, SG_INFO, "skipping duplicate add of scenery path:" << abspath.str());
-        continue;
-      }
+    // check for duplicates
+    PathList::const_iterator ex = std::find(fg_scenery.begin(), fg_scenery.end(), abspath);
+    if (ex != fg_scenery.end()) {
+        SG_LOG(SG_GENERAL, SG_INFO, "skipping duplicate add of scenery path:" << abspath);
+        return;
+    }
 
-      // tell the ResouceManager about the scenery path
-      // needed to load Models from this scenery path
-      simgear::ResourceManager::instance()->addBasePath(abspath.str(),
-        simgear::ResourceManager::PRIORITY_DEFAULT);
+    // tell the ResouceManager about the scenery path
+    // needed to load Models from this scenery path
+    simgear::ResourceManager::instance()->addBasePath(abspath.str(),
+                                                      simgear::ResourceManager::PRIORITY_DEFAULT);
 
-        simgear::Dir dir(abspath);
-        SGPath terrainDir(dir.file("Terrain"));
-        SGPath objectsDir(dir.file("Objects"));
+    simgear::Dir dir(abspath);
+    SGPath terrainDir(dir.file("Terrain"));
+    SGPath objectsDir(dir.file("Objects"));
 
-      // this code used to add *either* the base dir, OR add the
-      // Terrain and Objects subdirs, but the conditional logic was commented
-      // out, such that all three dirs are added. Unfortunately there's
-      // no information as to why the change was made.
-        fg_scenery.push_back(abspath.str());
-        if (secure) {
-          secure_fg_scenery.push_back(abspath.str());
-        }
+    // this code used to add *either* the base dir, OR add the
+    // Terrain and Objects subdirs, but the conditional logic was commented
+    // out, such that all three dirs are added. Unfortunately there's
+    // no information as to why the change was made.
+    fg_scenery.push_back(abspath);
+    if (secure) {
+        secure_fg_scenery.push_back(abspath);
+    }
 
-        if (terrainDir.exists()) {
-          fg_scenery.push_back(terrainDir.str());
-        }
+    if (terrainDir.exists()) {
+        fg_scenery.push_back(terrainDir);
+    }
 
-        if (objectsDir.exists()) {
-          fg_scenery.push_back(objectsDir.str());
-        }
+    if (objectsDir.exists()) {
+        fg_scenery.push_back(objectsDir);
+    }
 
-        // insert a marker for FGTileEntry::load(), so that
-        // FG_SCENERY=A:B becomes list ["A/Terrain", "A/Objects", "",
-        // "B/Terrain", "B/Objects", ""]
-        fg_scenery.push_back("");
+    // insert a marker for FGTileEntry::load(), so that
+    // FG_SCENERY=A:B becomes list ["A/Terrain", "A/Objects", "",
+    // "B/Terrain", "B/Objects", ""]
+    fg_scenery.push_back(SGPath());
 
-      // make scenery dirs available to Nasal
-        SGPropertyNode* n = sim->getChild("fg-scenery", propIndex++, true);
-        n->setStringValue(abspath.str());
-        n->setAttribute(SGPropertyNode::WRITE, false);
-
-        // temporary fix so these values survive reset
-        n->setAttribute(SGPropertyNode::PRESERVE, true);
-    } // of path list iteration
+    // make scenery dirs available to Nasal
+    SGPropertyNode* n = sim->getChild("fg-scenery", propIndex++, true);
+    n->setStringValue(abspath.utf8Str());
+    n->setAttribute(SGPropertyNode::WRITE, false);
+    
+    // temporary fix so these values survive reset
+    n->setAttribute(SGPropertyNode::PRESERVE, true);
 }
 
 void FGGlobals::clear_fg_scenery()
@@ -407,18 +412,18 @@ void FGGlobals::set_catalog_aircraft_path(const SGPath& path)
     catalog_aircraft_dir = path;
 }
 
-string_list FGGlobals::get_aircraft_paths() const
+PathList FGGlobals::get_aircraft_paths() const
 {
-    string_list r;
+    PathList r;
     if (!catalog_aircraft_dir.isNull()) {
-        r.push_back(catalog_aircraft_dir.str());
+        r.push_back(catalog_aircraft_dir);
     }
 
     r.insert(r.end(), fg_aircraft_dirs.begin(), fg_aircraft_dirs.end());
     return r;
 }
 
-void FGGlobals::append_aircraft_path(const std::string& path)
+void FGGlobals::append_aircraft_path(const SGPath& path)
 {
   SGPath dirPath(path);
   if (!dirPath.exists()) {
@@ -438,13 +443,11 @@ void FGGlobals::append_aircraft_path(const std::string& path)
       dirPath = acSubdir;
   }
 
-  std::string abspath = dirPath.realpath();
-  fg_aircraft_dirs.push_back(abspath);
+  fg_aircraft_dirs.push_back(dirPath.realpath());
 }
 
-void FGGlobals::append_aircraft_paths(const std::string& path)
+void FGGlobals::append_aircraft_paths(const PathList& paths)
 {
-  string_list paths = sgPathSplit(path);
   for (unsigned int p = 0; p<paths.size(); ++p) {
     append_aircraft_path(paths[p]);
   }
diff --git a/src/Main/globals.hxx b/src/Main/globals.hxx
index 2d83bcaed..6b6d07d8a 100644
--- a/src/Main/globals.hxx
+++ b/src/Main/globals.hxx
@@ -95,7 +95,7 @@ private:
     double sim_time_sec;
 
     // Root of FlightGear data tree
-    std::string fg_root;
+    SGPath fg_root;
 
     /**
      * locations to search for (non-scenery) data. 
@@ -103,11 +103,11 @@ private:
     PathList additional_data_paths;
     
     // Users home directory for data
-    std::string fg_home;
+    SGPath fg_home;
 
     // Roots of FlightGear scenery tree
-    string_list fg_scenery;
-    string_list secure_fg_scenery;
+    PathList fg_scenery;
+    PathList secure_fg_scenery;
 
     std::string browser;
 
@@ -130,7 +130,7 @@ private:
     FGTACANList *channellist;
 
     /// roots of Aircraft trees
-    string_list fg_aircraft_dirs;
+    PathList fg_aircraft_dirs;
     SGPath catalog_aircraft_dir;
 
     bool haveUserSettings;
@@ -191,8 +191,8 @@ public:
     inline void inc_sim_time_sec (double dt) { sim_time_sec += dt; }
     inline void set_sim_time_sec (double t) { sim_time_sec = t; }
 
-    inline const std::string &get_fg_root () const { return fg_root; }
-    void set_fg_root (const std::string &root);
+    const SGPath &get_fg_root () const { return fg_root; }
+    void set_fg_root (const SGPath&root);
 
     /**
      * Get list of data locations. fg_root is always the final item in the
@@ -214,11 +214,11 @@ public:
      */
     SGPath find_data_dir(const std::string& pathSuffix) const;
     
-    inline const std::string &get_fg_home () const { return fg_home; }
-    void set_fg_home (const std::string &home);
+    const SGPath &get_fg_home () const { return fg_home; }
+    void set_fg_home (const SGPath &home);
 
-    inline const string_list &get_fg_scenery () const { return fg_scenery; }
-    inline const string_list &get_secure_fg_scenery () const { return secure_fg_scenery; }
+    const PathList &get_fg_scenery () const { return fg_scenery; }
+    const PathList &get_secure_fg_scenery () const { return secure_fg_scenery; }
     /**
      * Add a scenery directory
      *
@@ -227,8 +227,10 @@ public:
      * obtained from the property tree (e.g. /sim/terrasync/scenery-dir)
      * or other Nasal-writable places
      */ 
-    void append_fg_scenery (const std::string &scenery, bool secure = false);
+    void append_fg_scenery (const SGPath &scenery, bool secure = false);
 
+    void append_fg_scenery (const PathList &scenery, bool secure = false);
+    
     void clear_fg_scenery();
 
     /**
@@ -238,10 +240,10 @@ public:
      */
     void set_catalog_aircraft_path(const SGPath& path);
 
-    string_list get_aircraft_paths() const;
+    PathList get_aircraft_paths() const;
 
-    void append_aircraft_path(const std::string& path);
-    void append_aircraft_paths(const std::string& path);
+    void append_aircraft_path(const SGPath& path);
+    void append_aircraft_paths(const PathList& path);
     
     /**
      * Given a path to an aircraft-related resource file, resolve it
diff --git a/src/Main/main.cxx b/src/Main/main.cxx
index 791fecd4b..17c7f6c90 100644
--- a/src/Main/main.cxx
+++ b/src/Main/main.cxx
@@ -293,7 +293,7 @@ static void fgIdleFunction ( void ) {
         flightgear::initPosition();
         flightgear::initTowerLocationListener();
         
-        simgear::SGModelLib::init(globals->get_fg_root(), globals->get_props());
+        simgear::SGModelLib::init(globals->get_fg_root().local8BitStr(), globals->get_props());
         
         TimeManager* timeManager = (TimeManager*) globals->get_subsystem("time");
         timeManager->init();
diff --git a/src/Main/options.cxx b/src/Main/options.cxx
index 659c052c1..75199e744 100644
--- a/src/Main/options.cxx
+++ b/src/Main/options.cxx
@@ -852,15 +852,16 @@ fgOptRoc( const char *arg )
 static int
 fgOptFgScenery( const char *arg )
 {
-    globals->append_fg_scenery(arg, true);
+    globals->append_fg_scenery(SGPath::pathsFromLocal8Bit(arg), true);
     return FG_OPTIONS_OK;
 }
 
 static int
 fgOptTerrasyncDir( const char *arg )
 {
-    globals->append_fg_scenery(arg, true);
-    fgSetString("/sim/terrasync/scenery-dir", arg);
+    SGPath p = SGPath::fromLocal8Bit(arg);
+    globals->append_fg_scenery(p, true);
+    fgSetString("/sim/terrasync/scenery-dir", p.utf8Str());
     return FG_OPTIONS_OK;
 }
 
@@ -1340,8 +1341,8 @@ fgOptVersion( const char *arg )
     cerr << "FG_SCENERY=";
 
     int didsome = 0;
-    string_list scn = globals->get_fg_scenery();
-    for (string_list::const_iterator it = scn.begin(); it != scn.end(); it++)
+    PathList scn = globals->get_fg_scenery();
+    for (PathList::const_iterator it = scn.begin(); it != scn.end(); it++)
     {
         if (didsome) cerr << ":";
         didsome++;
@@ -2007,7 +2008,7 @@ void Options::init(int argc, char **argv, const SGPath& appDataPath)
 // fg-root/fg-home/fg-aircraft and hence control what files Nasal can access
   std::string name_for_error = homedir.empty() ? appDataConfig.str() : config.str();
   if( ! hostname.empty() ) {
-    config.set(globals->get_fg_root());
+    config = globals->get_fg_root();
     config.append( "system.fgfsrc" );
     config.concat( "." );
     config.concat( hostname );
@@ -2018,7 +2019,7 @@ void Options::init(int argc, char **argv, const SGPath& appDataPath)
     }
   }
 
-  config.set(globals->get_fg_root());
+  config = globals->get_fg_root();
   config.append( "system.fgfsrc" );
   if (config.exists()) {
     flightgear::fatalMessageBox("Unsupported configuration",
@@ -2029,13 +2030,14 @@ void Options::init(int argc, char **argv, const SGPath& appDataPath)
 
 void Options::initPaths()
 {
-    BOOST_FOREACH(const string& paths, valuesForOption("fg-aircraft")) {
+    BOOST_FOREACH(const string& pathOpt, valuesForOption("fg-aircraft")) {
+        PathList paths = SGPath::pathsFromLocal8Bit(pathOpt);
         globals->append_aircraft_paths(paths);
     }
 
     const char* envp = ::getenv("FG_AIRCRAFT");
     if (envp) {
-        globals->append_aircraft_paths(envp);
+        globals->append_aircraft_paths(SGPath::pathsFromEnv("FG_AIRCRAFT"));
     }
 
 }
@@ -2057,22 +2059,22 @@ void Options::initAircraft()
   }
     
   if (p->showAircraft) {
-	vector<SGPath> path_list;
+	PathList path_list;
 
     fgOptLogLevel( "alert" );
 
     // First place to check is the 'Aircraft' sub-directory in $FG_ROOT
 
-	path_list.push_back( SGPath( globals->get_fg_root() ) );
-	path_list.back().append("Aircraft");
+      SGPath rootAircraft = globals->get_fg_root();
+      rootAircraft.append("Aircraft");
+	path_list.push_back(rootAircraft);
 
     // Additionally, aircraft may also be found in user-defined places
 	// (via $FG_AIRCRAFT or with the '--fg-aircraft' option)
+      PathList aircraft_paths = globals->get_aircraft_paths();
 
-	string_list aircraft_paths = globals->get_aircraft_paths();
-	for (string_list::iterator it = aircraft_paths.begin();
-		 it != aircraft_paths.end(); ++it)
-	  path_list.push_back( SGPath(*it));
+      path_list.insert(path_list.end(), aircraft_paths.begin(),
+                       aircraft_paths.end());
 
     fgShowAircraft(path_list);
     exit(0);
@@ -2354,7 +2356,7 @@ OptionResult Options::processOptions()
 // now options are process, do supplemental fixup
   const char *envp = ::getenv( "FG_SCENERY" );
   if (envp) {
-    globals->append_fg_scenery(envp, true);
+      globals->append_fg_scenery(SGPath::pathsFromEnv("FG_SCENERY"), true);
   }
 
 // download dir fix-up
@@ -2394,10 +2396,10 @@ OptionResult Options::processOptions()
     // always add the terrasync location, regardless of whether terrasync
     // is enabled or not. This allows us to toggle terrasync on/off at
     // runtime and have things work as expected
-    const string_list& scenery_paths(globals->get_fg_scenery());
-    if (std::find(scenery_paths.begin(), scenery_paths.end(), terrasyncDir) == scenery_paths.end()) {
+    const PathList& scenery_paths(globals->get_fg_scenery());
+    if (std::find(scenery_paths.begin(), scenery_paths.end(), SGPath(terrasyncDir)) == scenery_paths.end()) {
         // terrasync dir is not in the scenery paths, add it
-        globals->append_fg_scenery(terrasyncDir);
+        globals->append_fg_scenery(SGPath(terrasyncDir));
     }
 
     if (addFGDataScenery) {
@@ -2405,7 +2407,7 @@ OptionResult Options::processOptions()
         // ensure this path is added last
         SGPath root(globals->get_fg_root());
         root.append("Scenery");
-        globals->append_fg_scenery(root.str());
+        globals->append_fg_scenery(root);
     }
 
   return FG_OPTIONS_OK;
@@ -2544,20 +2546,20 @@ void Options::showUsage() const
 }
   
 #if defined(__CYGWIN__)
-string Options::platformDefaultRoot() const
+SGPath Options::platformDefaultRoot() const
 {
   return "../data";
 }
 
 #elif defined(SG_WINDOWS)
-string Options::platformDefaultRoot() const
+SGPath Options::platformDefaultRoot() const
 {
   return "..\\data";
 }
 #elif defined(SG_MAC)
 // platformDefaultRoot defined in CocoaHelpers.mm
 #else
-string Options::platformDefaultRoot() const
+SGPath Options::platformDefaultRoot() const
 {
   return PKGLIBDIR;
 }
@@ -2565,24 +2567,24 @@ string Options::platformDefaultRoot() const
   
 void Options::setupRoot(int argc, char **argv)
 {
-    string root;
+    SGPath root;
     bool usingDefaultRoot = false;
 
   if (isOptionSet("fg-root")) {
-    root = valueForOption("fg-root"); // easy!
-    SG_LOG(SG_GENERAL, SG_INFO, "set from command-line argument: fg_root = " << root );
+      root = SGPath::fromLocal8Bit(valueForOption("fg-root").c_str()); // easy!
+      SG_LOG(SG_GENERAL, SG_INFO, "set from command-line argument: fg_root = " << root );
   } else {
   // Next check if fg-root is set as an env variable
     char *envp = ::getenv( "FG_ROOT" );
     if ( envp != NULL ) {
-      root = envp;
-      SG_LOG(SG_GENERAL, SG_INFO, "set from FG_ROOT env var: fg_root = " << root );
+        root = SGPath::fromLocal8Bit(envp);
+        SG_LOG(SG_GENERAL, SG_INFO, "set from FG_ROOT env var: fg_root = " << root );
     } else {
 #if defined(HAVE_QT)
         flightgear::initApp(argc, argv);
         root = SetupRootDialog::restoreUserSelectedRoot();
 #endif
-        if (root.empty()) {
+        if (root.isNull()) {
             usingDefaultRoot = true;
             root = platformDefaultRoot();
             SG_LOG(SG_GENERAL, SG_INFO, "platform default fg_root = " << root );
diff --git a/src/Main/options.hxx b/src/Main/options.hxx
index 4f618213b..3679b72ff 100644
--- a/src/Main/options.hxx
+++ b/src/Main/options.hxx
@@ -142,7 +142,7 @@ public:
    */
   static bool checkForArg(int argc, char* argv[], const char* arg);
 
-      std::string platformDefaultRoot() const;
+      SGPath platformDefaultRoot() const;
 private:
   void showUsage() const;
   
diff --git a/src/Main/util.cxx b/src/Main/util.cxx
index a661a5212..3269a379f 100644
--- a/src/Main/util.cxx
+++ b/src/Main/util.cxx
@@ -92,8 +92,8 @@ void fgInitAllowedPaths()
     }
     read_allowed_paths.clear();
     write_allowed_paths.clear();
-    std::string fg_root = SGPath(globals->get_fg_root()).realpath();
-    std::string fg_home = SGPath(globals->get_fg_home()).realpath();
+    std::string fg_root = globals->get_fg_root().realpath();
+    std::string fg_home = globals->get_fg_home().realpath();
 #if defined(_MSC_VER) /*for MS compilers */ || defined(_WIN32) /*needed for non MS windows compilers like MingW*/
      std::string sep = "\\";
 #else
@@ -103,32 +103,28 @@ void fgInitAllowedPaths()
     read_allowed_paths.push_back(fg_home + sep + "*");
     read_allowed_paths.push_back(fg_root);
     read_allowed_paths.push_back(fg_home);
-    string_list const aircraft_paths = globals->get_aircraft_paths();
-    string_list const scenery_paths = globals->get_secure_fg_scenery();
+
+    const PathList& aircraft_paths = globals->get_aircraft_paths();
+    const PathList& scenery_paths = globals->get_secure_fg_scenery();
     // not plain fg_scenery, to avoid making
     // /sim/terrasync/scenery-dir a security hole
+    PathList read_paths = aircraft_paths;
+    read_paths.insert(read_paths.end(), scenery_paths.begin(), scenery_paths.end());
 
-    const string_list * path_lists_to_add[] = {
-      &aircraft_paths,
-      &scenery_paths
-    };
 
-    for( size_t i = 0; i < sizeof(path_lists_to_add)/sizeof(path_lists_to_add[0]); i++ )
-    {
-      for( string_list::const_iterator it = path_lists_to_add[i]->begin(); it != path_lists_to_add[i]->end();++it )
+      for( PathList::const_iterator it = read_paths.begin(); it != read_paths.end(); ++it )
       {
         // if we get the initialization order wrong, better to have an
         // obvious error than a can-read-everything security hole...
-          if (it->empty() || fg_root.empty() || fg_home.empty()){
+          if (it->isNull() || fg_root.empty() || fg_home.empty()) {
               flightgear::fatalMessageBox("Nasal initialization error",
                  "Empty string in FG_ROOT, FG_HOME, FG_AIRCRAFT or FG_SCENERY",
                                    "or fgInitAllowedPaths() called too early");
               exit(-1);
           }
-          read_allowed_paths.push_back(SGPath(*it).realpath() + sep + "*");
-          read_allowed_paths.push_back(SGPath(*it).realpath());
+          read_allowed_paths.push_back(it->realpath() + sep + "*");
+          read_allowed_paths.push_back(it->realpath());
       }
-    }
 
     write_allowed_paths.push_back(fg_home + sep + "*.sav");
     write_allowed_paths.push_back(fg_home + sep + "*.log");
@@ -141,13 +137,14 @@ void fgInitAllowedPaths()
     write_allowed_paths.push_back(fg_home + sep + "Input" + sep + "Joysticks" + sep + "*.xml");
     
     // Check that it works
-    if(!fgValidatePath(globals->get_fg_home() + "/../no.log",true).empty() ||
-        !fgValidatePath(globals->get_fg_home() + "/no.logt",true).empty() ||
-        !fgValidatePath(globals->get_fg_home() + "/nolog",true).empty() ||
-        !fgValidatePath(globals->get_fg_home() + "no.log",true).empty() ||
-        !fgValidatePath(globals->get_fg_home() + "\\..\\no.log",false).empty() ||
-        fgValidatePath(globals->get_fg_home() + "/aircraft-data/yes..xml",true).empty() ||
-        fgValidatePath(globals->get_fg_root() + "/.\\yes.bmp",false).empty()) {
+    std::string homePath = globals->get_fg_home().utf8Str();
+    if(!fgValidatePath(homePath + "/../no.log",true).empty() ||
+        !fgValidatePath(homePath + "/no.logt",true).empty() ||
+        !fgValidatePath(homePath + "/nolog",true).empty() ||
+        !fgValidatePath(homePath + "no.log",true).empty() ||
+        !fgValidatePath(homePath + "\\..\\no.log",false).empty() ||
+        fgValidatePath(homePath + "/aircraft-data/yes..xml",true).empty() ||
+        fgValidatePath(homePath + "/.\\yes.bmp",false).empty()) {
             flightgear::fatalMessageBox("Nasal initialization error",
                                     "The FG_HOME directory must not be inside any of the FG_ROOT, FG_AIRCRAFT or FG_SCENERY directories",
                                     "(check that you have not accidentally included an extra :, as an empty part means the current directory)");
diff --git a/src/Navaids/NavDataCache.cxx b/src/Navaids/NavDataCache.cxx
index 99894a0fb..be8b1d606 100644
--- a/src/Navaids/NavDataCache.cxx
+++ b/src/Navaids/NavDataCache.cxx
@@ -1223,7 +1223,7 @@ void NavDataCache::doRebuild()
 
           d->flushDeferredOctreeUpdates();
 
-          string sceneryPaths = simgear::strutils::join(globals->get_fg_scenery(), ";");
+          string sceneryPaths = SGPath::join(globals->get_fg_scenery(), ";");
           writeStringProperty("scenery_paths", sceneryPaths);
 
           st.stamp();
diff --git a/src/Scenery/tilemgr.cxx b/src/Scenery/tilemgr.cxx
index 99a7cf915..a2498db97 100644
--- a/src/Scenery/tilemgr.cxx
+++ b/src/Scenery/tilemgr.cxx
@@ -165,10 +165,13 @@ void FGTileMgr::reinit()
     _options->setPropertyNode(globals->get_props());
     
     osgDB::FilePathList &fp = _options->getDatabasePathList();
-    const string_list &sc = globals->get_fg_scenery();
+    const PathList &sc = globals->get_fg_scenery();
     fp.clear();
-    std::copy(sc.begin(), sc.end(), back_inserter(fp));
-    _options->setPluginStringData("SimGear::FG_ROOT", globals->get_fg_root());
+    PathList::const_iterator it;
+    for (it = sc.begin(); it != sc.end(); ++it) {
+        fp.push_back(it->local8BitStr());
+    }
+    _options->setPluginStringData("SimGear::FG_ROOT", globals->get_fg_root().local8BitStr());
     
     if (_terra_sync) {
       _options->setPluginStringData("SimGear::TERRASYNC_ROOT", fgGetString("/sim/terrasync/scenery-dir"));
diff --git a/src/Sound/VoiceSynthesizer.cxx b/src/Sound/VoiceSynthesizer.cxx
index fb40b439c..0942e2a7d 100644
--- a/src/Sound/VoiceSynthesizer.cxx
+++ b/src/Sound/VoiceSynthesizer.cxx
@@ -58,8 +58,8 @@ void FLITEVoiceSynthesizer::WorkerThread::run()
 string FLITEVoiceSynthesizer::getVoicePath( voice_t voice )
 {
   if( voice < 0 || voice >= VOICE_UNKNOWN ) return string("");
-  string voicePath = globals->get_fg_root() + "/ATC/" + VOICE_FILES[voice];
-  return voicePath;
+  SGPath voicePath = globals->get_fg_root() / "ATC" /  VOICE_FILES[voice];
+  return voicePath.local8BitStr();
 }
 
 string FLITEVoiceSynthesizer::getVoicePath( const string & voice )
diff --git a/src/Sound/flitevoice.cxx b/src/Sound/flitevoice.cxx
index 2c98edd5a..c38e96154 100644
--- a/src/Sound/flitevoice.cxx
+++ b/src/Sound/flitevoice.cxx
@@ -38,10 +38,10 @@ FGFLITEVoice::FGFLITEVoice(FGVoiceMgr * mgr, const SGPropertyNode_ptr node, cons
 
   _sampleName = node->getStringValue("desc", node->getPath().c_str());
 
-  string voice = globals->get_fg_root() + "/ATC/" +
+    SGPath voice = globals->get_fg_root() / "ATC" /
       node->getStringValue("htsvoice", "cmu_us_arctic_slt.htsvoice");
 
-  _synthesizer = new FLITEVoiceSynthesizer(voice.c_str());
+  _synthesizer = new FLITEVoiceSynthesizer(voice.local8BitStr());
 
   SGSoundMgr *smgr = globals->get_subsystem<SGSoundMgr>();
   _sgr = smgr->find(sampleGroupRefName, true);
diff --git a/src/Traffic/Schedule.cxx b/src/Traffic/Schedule.cxx
index 09efa2dec..7e53cda06 100644
--- a/src/Traffic/Schedule.cxx
+++ b/src/Traffic/Schedule.cxx
@@ -343,9 +343,8 @@ SGPath FGAISchedule::resolveModelPath(const std::string& modelPath)
     }
     
     // check aircraft dirs
-    BOOST_FOREACH(std::string aircraftPath, globals->get_aircraft_paths()) {
-        SGPath mp(aircraftPath);
-        mp.append(modelPath);
+    BOOST_FOREACH(SGPath aircraftPath, globals->get_aircraft_paths()) {
+        SGPath mp = aircraftPath / modelPath;
         if (mp.exists()) {
             return mp;
         }
diff --git a/src/Traffic/TrafficMgr.cxx b/src/Traffic/TrafficMgr.cxx
index 2fe014091..73af68c4d 100644
--- a/src/Traffic/TrafficMgr.cxx
+++ b/src/Traffic/TrafficMgr.cxx
@@ -534,12 +534,14 @@ void FGTrafficManager::init()
         simgear::PathList dirs = globals->get_data_paths("AI/Traffic");
         
         // temporary flag to restrict loading while traffic data is found
-        // through terrasync /and/ fgdata. Ultimatley we *do* want to be able to
+        // through terrasync /and/ fgdata. Ultimately we *do* want to be able to
         // overlay sources.
         
         if (dirs.size() > 1) {
             SGPath p = dirs.back();
-            if (simgear::strutils::starts_with(p.str(), globals->get_fg_root())) {
+            if (simgear::strutils::starts_with(p.utf8Str(),
+                                               globals->get_fg_root().utf8Str()))
+            {
                 dirs.pop_back();
             }
         }
diff --git a/src/Viewer/fgviewer.cxx b/src/Viewer/fgviewer.cxx
index aa0fbf9a1..850a33a1b 100644
--- a/src/Viewer/fgviewer.cxx
+++ b/src/Viewer/fgviewer.cxx
@@ -180,21 +180,21 @@ fgviewerMain(int argc, char** argv)
 
     osgDB::FilePathList filePathList
         = osgDB::Registry::instance()->getDataFilePathList();
-    filePathList.push_back(globals->get_fg_root());
+    filePathList.push_back(globals->get_fg_root().local8BitStr());
 
-    string_list path_list = globals->get_fg_scenery();
+    const PathList& path_list = globals->get_fg_scenery();
     for (unsigned i = 0; i < path_list.size(); ++i) {
-        filePathList.push_back(path_list[i]);
+        filePathList.push_back(path_list[i].local8BitStr());
     }
 
     globals->set_matlib( new SGMaterialLib );
-    simgear::SGModelLib::init(globals->get_fg_root(), globals->get_props());
+    simgear::SGModelLib::init(globals->get_fg_root().local8BitStr(), globals->get_props());
 
     // Initialize the material property subsystem.
 
     SGPath mpath( globals->get_fg_root() );
     mpath.append( fgGetString("/sim/rendering/materials-file") );
-    if ( ! globals->get_matlib()->load(globals->get_fg_root(), mpath.str(),
+    if ( ! globals->get_matlib()->load(globals->get_fg_root().local8BitStr(), mpath.str(),
             globals->get_props()) ) {
         throw sg_io_exception("Error loading materials file", mpath);
     }
diff --git a/src/Viewer/renderer.cxx b/src/Viewer/renderer.cxx
index 552a880c8..8a3256b1a 100644
--- a/src/Viewer/renderer.cxx
+++ b/src/Viewer/renderer.cxx
@@ -1173,7 +1173,7 @@ FGRenderer::buildDeferredFullscreenCamera( flightgear::CameraInfo* info, const F
     g->setUseDisplayList(false);
     simgear::EffectGeode* eg = new simgear::EffectGeode;
     osg::ref_ptr<SGReaderWriterOptions> opt;
-    opt = SGReaderWriterOptions::fromPath(globals->get_fg_root());
+    opt = SGReaderWriterOptions::fromPath(globals->get_fg_root().local8BitStr());
     opt->setPropertyNode(globals->get_props());
     simgear::Effect* effect = simgear::makeEffect(pass->effect, true, opt.get());
     if (effect) {
@@ -1226,7 +1226,7 @@ FGRenderer::buildDeferredDisplayCamera( osg::Camera* camera, flightgear::CameraI
     g->setUseDisplayList(false); //DEBUG
     simgear::EffectGeode* eg = new simgear::EffectGeode;
     osg::ref_ptr<SGReaderWriterOptions> opt;
-    opt = SGReaderWriterOptions::fromPath(globals->get_fg_root());
+    opt = SGReaderWriterOptions::fromPath(globals->get_fg_root().local8BitStr());
     opt->setPropertyNode(globals->get_props());
     simgear::Effect* effect = simgear::makeEffect(stage->effect, true, opt.get());
     if (!effect) {
@@ -1459,7 +1459,7 @@ FGRenderer::setupView( void )
     // Moon diameter:    3,476 kilometers
     // Sun diameter: 1,390,000 kilometers
     osg::ref_ptr<SGReaderWriterOptions> opt;
-    opt = SGReaderWriterOptions::fromPath(globals->get_fg_root());
+    opt = SGReaderWriterOptions::fromPath(globals->get_fg_root().local8BitStr());
     opt->setPropertyNode(globals->get_props());
     _sky->build( 80000.0, 80000.0,
                   463.3, 361.8,
diff --git a/utils/fgpanel/FGPanelApplication.cxx b/utils/fgpanel/FGPanelApplication.cxx
index 3806f071e..f8aecf86a 100644
--- a/utils/fgpanel/FGPanelApplication.cxx
+++ b/utils/fgpanel/FGPanelApplication.cxx
@@ -71,18 +71,18 @@ inline static string ParseArgs( int argc, char ** argv, const char * token )
 
 // define default location of fgdata (use the same as for fgfs)
 #if defined(__CYGWIN__)
-inline static string platformDefaultRoot()
+inline static SGPath platformDefaultRoot()
 {
-  return "../data";
+  return SGPath("../data");
 }
 
 #elif defined(_WIN32)
-inline static string platformDefaultRoot()
+inline static SGPath platformDefaultRoot()
 {
-  return "..\\data";
+  return SGPath("..\\data");
 }
 #elif defined(__APPLE__)
-inline static string platformDefaultRoot()
+inline static SGPath platformDefaultRoot()
 {
   /*
    The following code looks for the base package inside the application
@@ -101,12 +101,12 @@ inline static string platformDefaultRoot()
   CFRelease(dataDir);
   CFRelease(path);
 
-  return root;
+  return SGPath(root);
 }
 #else
-inline static string platformDefaultRoot()
+inline static SGPath platformDefaultRoot()
 {
-  return PKGLIBDIR;
+  return SGPath(PKGLIBDIR);
 }
 #endif
 
@@ -122,7 +122,7 @@ FGPanelApplication::FGPanelApplication( int argc, char ** argv ) :
   FGCroppedTexture::registerTextureLoader( "png", &pngTextureLoader );
   FGCroppedTexture::registerTextureLoader( "rgb", &rgbTextureLoader );
 
-  ApplicationProperties::root = platformDefaultRoot();
+  ApplicationProperties::root = platformDefaultRoot().local8BitStr();
 
   string panelFilename;
   string fgRoot;