diff --git a/src/AIModel/AIFlightPlan.cxx b/src/AIModel/AIFlightPlan.cxx
index d99172274..7d1c6ae66 100644
--- a/src/AIModel/AIFlightPlan.cxx
+++ b/src/AIModel/AIFlightPlan.cxx
@@ -234,9 +234,9 @@ bool FGAIFlightPlan::parseProperties(const std::string& filename)
   
   SGPropertyNode root;
   try {
-    readProperties(path.str(), &root);
+    readProperties(path, &root);
   } catch (const sg_exception &e) {
-    SG_LOG(SG_AI, SG_ALERT, "Error reading AI flight plan: " << path.str()
+    SG_LOG(SG_AI, SG_ALERT, "Error reading AI flight plan: " << path
            << "message:" << e.getFormattedMessage());
     return false;
   }
diff --git a/src/AIModel/AIManager.cxx b/src/AIModel/AIManager.cxx
index 4faf23e59..fe9e4ee13 100644
--- a/src/AIModel/AIManager.cxx
+++ b/src/AIModel/AIManager.cxx
@@ -507,11 +507,11 @@ FGAIManager::loadScenarioFile(const std::string& filename)
     path.append("AI/" + filename + ".xml");
     try {
         SGPropertyNode_ptr root = new SGPropertyNode;
-        readProperties(path.str(), root);
+        readProperties(path, root);
         return root;
     } catch (const sg_exception &t) {
         SG_LOG(SG_AI, SG_ALERT, "Failed to load scenario '"
-            << path.str() << "': " << t.getFormattedMessage());
+            << path << "': " << t.getFormattedMessage());
     }
     return 0;
 }
diff --git a/src/AIModel/performancedb.cxx b/src/AIModel/performancedb.cxx
index 3a8ce5459..7b01e86fe 100644
--- a/src/AIModel/performancedb.cxx
+++ b/src/AIModel/performancedb.cxx
@@ -111,10 +111,10 @@ void PerformanceDB::load(const SGPath& filename)
 {
     SGPropertyNode root;
     try {
-        readProperties(filename.str(), &root);
+        readProperties(filename, &root);
     } catch (const sg_exception &) {
         SG_LOG(SG_AI, SG_ALERT,
-            "Error reading AI aircraft performance database: " << filename.str());
+            "Error reading AI aircraft performance database: " << filename);
         return;
     }
 
diff --git a/src/AIModel/submodel.cxx b/src/AIModel/submodel.cxx
index b3000f9a3..249fe1ade 100644
--- a/src/AIModel/submodel.cxx
+++ b/src/AIModel/submodel.cxx
@@ -484,12 +484,12 @@ void FGSubmodelMgr::setData(int id, const string& path, bool serviceable, const
     SGPath config = globals->resolve_aircraft_path(path);
     try {
         SG_LOG(SG_AI, SG_DEBUG,
-                "Submodels: Trying to read AI submodels file: " << config.str());
-        readProperties(config.str(), &root);
+                "Submodels: Trying to read AI submodels file: " << config);
+        readProperties(config, &root);
     }
     catch (const sg_exception &) {
         SG_LOG(SG_AI, SG_ALERT,
-                "Submodels: Unable to read AI submodels file: " << config.str());
+                "Submodels: Unable to read AI submodels file: " << config);
         return;
     }
 
diff --git a/src/ATC/ATISEncoder.cxx b/src/ATC/ATISEncoder.cxx
index 294bb8306..256166cd7 100644
--- a/src/ATC/ATISEncoder.cxx
+++ b/src/ATC/ATISEncoder.cxx
@@ -193,7 +193,7 @@ string ATISEncoder::encodeATIS( ATISInformationProvider * atisInformation )
     try
     {
       SGPath path = globals->resolve_maybe_aircraft_path("ATC/atis.xml");
-      readProperties( path.str(), atisSchemaNode );
+      readProperties( path, atisSchemaNode );
     }
     catch (const sg_exception& e)
     {
diff --git a/src/Aircraft/flightrecorder.cxx b/src/Aircraft/flightrecorder.cxx
index 34a03c18d..075ba17a3 100644
--- a/src/Aircraft/flightrecorder.cxx
+++ b/src/Aircraft/flightrecorder.cxx
@@ -180,7 +180,7 @@ FGFlightRecorder::getDefault(void)
         {
             try
             {
-                readProperties(path.str(), m_RecorderNode->getChild("config", 0 ,true), 0);
+                readProperties(path, m_RecorderNode->getChild("config", 0 ,true), 0);
                 ConfigNode = m_RecorderNode->getChild("config", 0 ,false);
             } catch (sg_io_exception &e)
             {
diff --git a/src/Airports/airport.cxx b/src/Airports/airport.cxx
index 879f3f224..c8be10102 100644
--- a/src/Airports/airport.cxx
+++ b/src/Airports/airport.cxx
@@ -564,7 +564,7 @@ void FGAirport::loadProcedures() const
     return;
   }
   
-  SG_LOG(SG_GENERAL, SG_INFO, ident() << ": loading procedures from " << path.str());
+  SG_LOG(SG_GENERAL, SG_INFO, ident() << ": loading procedures from " << path);
   RouteBase::loadAirportProcedures(path, const_cast<FGAirport*>(this));
 }
 
@@ -583,7 +583,7 @@ void FGAirport::loadSceneryDefinitions() const
   
   try {
     SGPropertyNode_ptr rootNode = new SGPropertyNode;
-    readProperties(path.str(), rootNode);
+    readProperties(path, rootNode);
     const_cast<FGAirport*>(this)->readThresholdData(rootNode);
   } catch (sg_exception& e) {
     SG_LOG(SG_NAVAID, SG_WARN, ident() << "loading threshold XML failed:" << e.getFormattedMessage());
@@ -691,7 +691,7 @@ void FGAirport::validateTowerData() const
   
   try {
     SGPropertyNode_ptr rootNode = new SGPropertyNode;
-    readProperties(path.str(), rootNode);
+    readProperties(path, rootNode);
     const_cast<FGAirport*>(this)->readTowerData(rootNode);
     mHasTower = true;
   } catch (sg_exception& e){
@@ -729,7 +729,7 @@ void FGAirport::validateILSData()
   
   try {
       SGPropertyNode_ptr rootNode = new SGPropertyNode;
-      readProperties(path.str(), rootNode);
+      readProperties(path, rootNode);
       readILSData(rootNode);
   } catch (sg_exception& e){
       SG_LOG(SG_NAVAID, SG_WARN, ident() << "loading ils XML failed:" << e.getFormattedMessage());
diff --git a/src/Airports/apt_loader.cxx b/src/Airports/apt_loader.cxx
index 0dd3512b4..781a078f0 100644
--- a/src/Airports/apt_loader.cxx
+++ b/src/Airports/apt_loader.cxx
@@ -89,12 +89,11 @@ public:
 
   void parseAPT(const SGPath &aptdb_file)
   {
-    std::string apt_dat = aptdb_file.str();
-    sg_gzifstream in(apt_dat);
+    sg_gzifstream in(aptdb_file);
 
     if ( !in.is_open() ) {
-      SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << apt_dat );
-      throw sg_io_exception("cannot open apt.dat file", apt_dat.c_str());
+      SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << aptdb_file );
+      throw sg_io_exception("cannot open apt.dat file", aptdb_file);
     }
 
     string line;
@@ -113,9 +112,8 @@ public:
         // First line indicates IBM ("I") or Macintosh ("A") line endings.
         if ( stripped_line != "I" && stripped_line != "A" ) {
           std::string pb = "invalid first line (neither 'I' nor 'A')";
-          SG_LOG( SG_GENERAL, SG_ALERT, apt_dat << ": " << pb);
-          throw sg_format_exception("cannot parse apt.dat file: " + pb,
-                                    apt_dat);
+          SG_LOG( SG_GENERAL, SG_ALERT, aptdb_file << ": " << pb);
+          throw sg_format_exception("cannot parse apt.dat file: " + pb, aptdb_file.utf8Str());
         }
       } else {     // second line of the file
         std::istringstream s(line);
@@ -126,7 +124,7 @@ public:
       }
     } // end of the apt.dat header
 
-    throwExceptionIfStreamError(in, "apt.dat", apt_dat);
+    throwExceptionIfStreamError(in, "apt.dat", aptdb_file.utf8Str());
 
     while ( std::getline(in, line) ) {
       // 'line' may end with an \r character, see above
@@ -202,7 +200,7 @@ public:
       }
     }
 
-    throwExceptionIfStreamError(in, "apt.dat", apt_dat);
+    throwExceptionIfStreamError(in, "apt.dat", aptdb_file.utf8Str());
     finishAirport();
   }
   
@@ -569,7 +567,7 @@ bool airportDBLoad( const SGPath &aptdb_file )
   
 bool metarDataLoad(const SGPath& metar_file)
 {
-  sg_gzifstream metar_in( metar_file.str() );
+  sg_gzifstream metar_in( metar_file );
   if ( !metar_in.is_open() ) {
     SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << metar_file );
     return false;
diff --git a/src/Airports/sidstar.cxx b/src/Airports/sidstar.cxx
index af7a020c9..22aa32179 100644
--- a/src/Airports/sidstar.cxx
+++ b/src/Airports/sidstar.cxx
@@ -52,10 +52,10 @@ void FGSidStar::load(SGPath filename) {
   string runway;
   string name;
   try {
-      readProperties(filename.str(), &root);
+      readProperties(filename, &root);
   } catch (const sg_exception &) {
       SG_LOG(SG_GENERAL, SG_ALERT,
-       "Error reading AI flight plan: " << filename.str());
+       "Error reading AI flight plan: " << filename);
        // cout << path.str() << endl;
      return;
   }
diff --git a/src/Airports/xmlloader.cxx b/src/Airports/xmlloader.cxx
index 9bbc3e750..dc24ec6c1 100644
--- a/src/Airports/xmlloader.cxx
+++ b/src/Airports/xmlloader.cxx
@@ -54,7 +54,7 @@ void XMLLoader::load(FGGroundNetwork* net)
   t.stamp();
   try {
       FGGroundNetXMLLoader visitor(net);
-      readXML(path.str(), visitor);
+      readXML(path.local8BitStr(), visitor);
   } catch (sg_exception& e) {
     SG_LOG(SG_NAVAID, SG_INFO, "parsing groundnet XML failed:" << e.getFormattedMessage());
   }
@@ -105,8 +105,8 @@ bool XMLLoader::loadAirportXMLDataIntoVisitor(const string& aICAO,
     return false;
   }
 
-  SG_LOG(SG_GENERAL, SG_DEBUG, "loadAirportXMLDataIntoVisitor: loading from " << path.str());
-  readXML(path.str(), aVisitor);
+  SG_LOG(SG_GENERAL, SG_DEBUG, "loadAirportXMLDataIntoVisitor: loading from " << path);
+  readXML(path.local8BitStr(), aVisitor);
   return true;
 }
 
diff --git a/src/Autopilot/autopilotgroup.cxx b/src/Autopilot/autopilotgroup.cxx
index 199a14b94..ada473cb5 100644
--- a/src/Autopilot/autopilotgroup.cxx
+++ b/src/Autopilot/autopilotgroup.cxx
@@ -197,13 +197,13 @@ void FGXMLAutopilotGroup::addAutopilotFromFile( const std::string& name,
   (
     SG_AUTOPILOT,
     SG_INFO,
-    "Reading property-rule configuration from " << config.str()
+    "Reading property-rule configuration from " << config
   );
 
   try
   {
     SGPropertyNode_ptr configNode = new SGPropertyNode();
-    readProperties( config.str(), configNode );
+    readProperties( config, configNode );
 
     SG_LOG(SG_AUTOPILOT, SG_INFO, "adding  property-rule subsystem " << name);
     addAutopilot(name, apNode, configNode);
@@ -214,7 +214,7 @@ void FGXMLAutopilotGroup::addAutopilotFromFile( const std::string& name,
     (
       SG_AUTOPILOT,
       SG_ALERT,
-      "Failed to load property-rule configuration: " << config.str()
+      "Failed to load property-rule configuration: " << config
                                              << ": " << e.getMessage()
     );
     return;
diff --git a/src/Autopilot/route_mgr.cxx b/src/Autopilot/route_mgr.cxx
index f58c57ac4..bae5b1d23 100644
--- a/src/Autopilot/route_mgr.cxx
+++ b/src/Autopilot/route_mgr.cxx
@@ -359,7 +359,7 @@ void FGRouteMgr::postinit()
   
   SGPath path(_pathNode->getStringValue());
   if (!path.isNull()) {
-    SG_LOG(SG_AUTOPILOT, SG_INFO, "loading flight-plan from: " << path.str());
+    SG_LOG(SG_AUTOPILOT, SG_INFO, "loading flight-plan from: " << path);
     loadRoute(path);
   }
   
diff --git a/src/Canvas/FGCanvasSystemAdapter.cxx b/src/Canvas/FGCanvasSystemAdapter.cxx
index 894ca0bdc..f31ab12cf 100644
--- a/src/Canvas/FGCanvasSystemAdapter.cxx
+++ b/src/Canvas/FGCanvasSystemAdapter.cxx
@@ -48,16 +48,16 @@ namespace canvas
     (
       SG_GL,
       SG_INFO,
-      "canvas::Text: using font file " << path.str()
+      "canvas::Text: using font file " << path
     );
 
-    simgear::canvas::FontPtr font = osgText::readFontFile(path.c_str());
+    simgear::canvas::FontPtr font = osgText::readFontFile(path.local8BitStr());
     if( !font )
       SG_LOG
       (
         SG_GL,
         SG_ALERT,
-        "canvas::Text: Failed to open font file " << path.c_str()
+        "canvas::Text: Failed to open font file " << path
       );
 
     return font;
diff --git a/src/Cockpit/cockpitDisplayManager.cxx b/src/Cockpit/cockpitDisplayManager.cxx
index 18e6e7d8a..4c6d338f1 100644
--- a/src/Cockpit/cockpitDisplayManager.cxx
+++ b/src/Cockpit/cockpitDisplayManager.cxx
@@ -65,10 +65,10 @@ void CockpitDisplayManager::init()
   }
 
   SGPath config = globals->resolve_aircraft_path(path_n->getStringValue());
-  SG_LOG( SG_COCKPIT, SG_INFO, "Reading cockpit displays from " << config.str() );
+  SG_LOG( SG_COCKPIT, SG_INFO, "Reading cockpit displays from " << config );
 
   try {
-    readProperties( config.str(), config_props );
+    readProperties( config, config_props );
     if (!build(config_props)) {
       throw sg_exception(
                     "Detected an internal inconsistency in the instrumentation\n"
@@ -76,7 +76,7 @@ void CockpitDisplayManager::init()
     }
   } catch (const sg_exception& e) {
     SG_LOG(SG_COCKPIT, SG_ALERT, "Failed to load instrumentation system model: "
-                    << config.str() << ":" << e.getFormattedMessage() );
+                    << config << ":" << e.getFormattedMessage() );
   }
 
   // bind() created instruments before init.
diff --git a/src/Cockpit/panel_io.cxx b/src/Cockpit/panel_io.cxx
index f05d057f1..cb12f5a7d 100644
--- a/src/Cockpit/panel_io.cxx
+++ b/src/Cockpit/panel_io.cxx
@@ -844,7 +844,7 @@ fgReadPanel (const string &relative_path)
   SGPropertyNode root;
   
   try {
-    readProperties(path.str(), &root);
+    readProperties(path, &root);
   } catch (const sg_exception &e) {
     guiErrorMessage("Error reading panel: ", e);
     return 0;
diff --git a/src/FDM/JSBSim/JSBSim.cxx b/src/FDM/JSBSim/JSBSim.cxx
index b94a900a8..d825a4262 100644
--- a/src/FDM/JSBSim/JSBSim.cxx
+++ b/src/FDM/JSBSim/JSBSim.cxx
@@ -233,9 +233,9 @@ FGJSBsim::FGJSBsim( double dt )
 
     fdmex->Setdt( dt );
 
-    result = fdmex->LoadModel( aircraft_path.str(),
-                               engine_path.str(),
-                               systems_path.str(),
+    result = fdmex->LoadModel( aircraft_path.local8BitStr(),
+                               engine_path.local8BitStr(),
+                               systems_path.local8BitStr(),
                                fgGetString("/sim/aero"), false );
 
     if (result) {
diff --git a/src/FDM/UIUCModel/uiuc_wrapper.cpp b/src/FDM/UIUCModel/uiuc_wrapper.cpp
index fd3fcf8ea..297c0e6b2 100644
--- a/src/FDM/UIUCModel/uiuc_wrapper.cpp
+++ b/src/FDM/UIUCModel/uiuc_wrapper.cpp
@@ -321,9 +321,9 @@ void uiuc_init_aeromodel ()
   // Called once from uiuc_init_2_wrapper
   SGPath path(fgGetString("/sim/aircraft-dir"));
   path.append("aircraft.dat");
-  std::cout << "We are using "<< path.str() << std::endl;
+  std::cout << "We are using "<< path << std::endl;
   uiuc_initializemaps(); // Initialize the <string,int> maps
-  uiuc_menu(path.str());   // Read the specified aircraft file 
+  uiuc_menu(path.local8BitStr());   // Read the specified aircraft file
 }
 
 void uiuc_force_moment(double dt)
diff --git a/src/FDM/YASim/YASim.cxx b/src/FDM/YASim/YASim.cxx
index 07163676a..22073380a 100644
--- a/src/FDM/YASim/YASim.cxx
+++ b/src/FDM/YASim/YASim.cxx
@@ -170,10 +170,10 @@ void YASim::init()
     f.append(fgGetString("/sim/aero"));
     f.concat(".xml");
     try {
-        readXML(f.str(), *_fdm);
+        readXML(f.local8BitStr(), *_fdm);
     } catch (const sg_exception &e) {
         SG_LOG(SG_FLIGHT, SG_ALERT,
-               "Error reading YASim FDM: '" << f.str() << "'" << std::endl
+               "Error reading YASim FDM: '" << f << "'" << std::endl
                << e.getFormattedMessage());
         throw e;
     }
diff --git a/src/GUI/AircraftModel.cxx b/src/GUI/AircraftModel.cxx
index 5783a1237..774608d1c 100644
--- a/src/GUI/AircraftModel.cxx
+++ b/src/GUI/AircraftModel.cxx
@@ -522,7 +522,7 @@ void AircraftItemModel::scanDirs()
 
     SGPath rootAircraft(globals->get_fg_root());
     rootAircraft.append("Aircraft");
-    dirs << QString::fromStdString(rootAircraft.str());
+    dirs << QString::fromStdString(rootAircraft.utf8Str());
 
     m_scanThread = new AircraftScanThread(dirs);
     connect(m_scanThread, &AircraftScanThread::finished, this,
@@ -713,7 +713,7 @@ QVariant AircraftItemModel::dataFromPackage(const PackageRef& item, quint32 vari
     } else if (role == AircraftPathRole) {
         InstallRef i = item->existingInstall();
         if (i.valid()) {
-            return QString::fromStdString(i->primarySetPath().str());
+            return QString::fromStdString(i->primarySetPath().utf8Str());
         }
     } else if (role == AircraftPackageIdRole) {
         return QString::fromStdString(item->variants()[variantIndex]);
@@ -794,7 +794,7 @@ QVariant AircraftItemModel::packageThumbnail(PackageRef p, int index, bool downl
             path.append(p->thumbnails()[index]);
             if (path.exists()) {
                 QPixmap pix;
-                pix.load(QString::fromStdString(path.str()));
+                pix.load(QString::fromStdString(path.utf8Str()));
                 // resize to the standard size
                 if (pix.height() > STANDARD_THUMBNAIL_HEIGHT) {
                     pix = pix.scaledToHeight(STANDARD_THUMBNAIL_HEIGHT);
diff --git a/src/GUI/CocoaHelpers.mm b/src/GUI/CocoaHelpers.mm
index 493e9458f..126b17c21 100644
--- a/src/GUI/CocoaHelpers.mm
+++ b/src/GUI/CocoaHelpers.mm
@@ -52,7 +52,7 @@ std::string stdStringFromCocoa(NSString* s)
 
 NSURL* pathToNSURL(const SGPath& aPath)
 {
-    return [NSURL fileURLWithPath:stdStringToCocoa(aPath.str())];
+    return [NSURL fileURLWithPath:stdStringToCocoa(aPath.utf8Str())];
 }
 
 SGPath URLToPath(NSURL* url)
diff --git a/src/GUI/QtFileDialog.cxx b/src/GUI/QtFileDialog.cxx
index 5d140db91..effae6650 100644
--- a/src/GUI/QtFileDialog.cxx
+++ b/src/GUI/QtFileDialog.cxx
@@ -52,7 +52,7 @@ void QtFileDialog::exec()
         }
         filter=filter+*it;
     }
-    QFileDialog dlg(0,QString::fromStdString(_title),QString::fromStdString(_initialPath.str()),QString::fromStdString(filter));
+    QFileDialog dlg(0,QString::fromStdString(_title),QString::fromStdString(_initialPath.utf8Str()),QString::fromStdString(filter));
     if (_usage==USE_SAVE_FILE) {
         dlg.setAcceptMode(QFileDialog::AcceptSave);
     }
diff --git a/src/GUI/QtLauncher.cxx b/src/GUI/QtLauncher.cxx
index 8e74eb257..f407f43fc 100644
--- a/src/GUI/QtLauncher.cxx
+++ b/src/GUI/QtLauncher.cxx
@@ -655,7 +655,7 @@ void QtLauncher::setSceneryPaths()
     SGPath terraSyncDir(downloadDir.toStdString());
     terraSyncDir.append("TerraSync");
     if (terraSyncDir.exists()) {
-        globals->append_fg_scenery(terraSyncDir.str());
+        globals->append_fg_scenery(terraSyncDir.utf8Str());
     }
 
 }
diff --git a/src/Input/fgjs.cxx b/src/Input/fgjs.cxx
index d849f3ce6..76a20b37f 100644
--- a/src/Input/fgjs.cxx
+++ b/src/Input/fgjs.cxx
@@ -136,7 +136,7 @@ int main( int argc, char *argv[] ) {
 
     SGPropertyNode *templatetree = new SGPropertyNode();
     try {
-        readProperties(templatefile.str().c_str(), templatetree);
+        readProperties(templatefile, templatetree);
     } catch (sg_io_exception & e) {
         cout << e.getFormattedMessage ();
     }
diff --git a/src/Main/fg_commands.cxx b/src/Main/fg_commands.cxx
index 1e93a0b7b..98ea4b67c 100644
--- a/src/Main/fg_commands.cxx
+++ b/src/Main/fg_commands.cxx
@@ -1162,7 +1162,7 @@ do_load_xml_to_proptree(const SGPropertyNode * arg)
         targetnode = const_cast<SGPropertyNode *>(arg)->getNode("data", true);
 
     try {
-        readProperties(validated_path.c_str(), targetnode, true);
+        readProperties(validated_path, targetnode, true);
     } catch (const sg_exception &e) {
         SG_LOG(SG_IO, SG_WARN, "loadxml: " << e.getFormattedMessage());
         return false;
@@ -1247,7 +1247,7 @@ do_save_xml_from_proptree(const SGPropertyNode * arg)
         return false;
 
     try {
-        writeProperties (validated_path.c_str(), sourcenode, true);
+        writeProperties (validated_path, sourcenode, true);
     } catch (const sg_exception &e) {
         SG_LOG(SG_IO, SG_WARN, "savexml: " << e.getFormattedMessage());
         return false;
diff --git a/src/Navaids/FlightPlan.cxx b/src/Navaids/FlightPlan.cxx
index 89e1f5f41..926688e65 100644
--- a/src/Navaids/FlightPlan.cxx
+++ b/src/Navaids/FlightPlan.cxx
@@ -922,7 +922,7 @@ WayptRef FlightPlan::parseVersion1XMLWaypt(SGPropertyNode* aWP)
 bool FlightPlan::loadPlainTextFormat(const SGPath& path)
 {
   try {
-    sg_gzifstream in(path.str().c_str());
+    sg_gzifstream in(path);
     if (!in.is_open()) {
       throw sg_io_exception("Cannot open file for reading.");
     }
diff --git a/src/Navaids/NavDataCache.cxx b/src/Navaids/NavDataCache.cxx
index ea83e861d..99894a0fb 100644
--- a/src/Navaids/NavDataCache.cxx
+++ b/src/Navaids/NavDataCache.cxx
@@ -263,7 +263,7 @@ public:
         SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
       // see http://code.google.com/p/flightgear-bugs/issues/detail?id=1055
       // for the UTF8 / path logic here
-	std::string pathUtf8 = simgear::strutils::convertWindowsLocal8BitToUtf8(path.str());
+      std::string pathUtf8 = path.utf8Str();
     sqlite3_open_v2(pathUtf8.c_str(), &db, openFlags, NULL);
 
     sqlite3_stmt_ptr checkTables =
@@ -978,10 +978,10 @@ FGPositioned* NavDataCache::NavDataCachePrivate::loadById(sqlite3_int64 rowid,
 bool NavDataCache::NavDataCachePrivate::isCachedFileModified(const SGPath& path, bool verbose)
 {
   if (!path.exists()) {
-    throw sg_io_exception("isCachedFileModified: Missing file:" + path.str());
+    throw sg_io_exception("isCachedFileModified: Missing file:", path);
   }
 
-  sqlite_bind_temp_stdstring(statCacheCheck, 1, path.str());
+  sqlite_bind_temp_stdstring(statCacheCheck, 1, path.utf8Str());
   bool isModified = true;
   sgDebugPriority logLevel = verbose ? SG_WARN : SG_DEBUG;
   if (execSelect(statCacheCheck)) {
@@ -1336,7 +1336,7 @@ bool NavDataCache::isCachedFileModified(const SGPath& path) const
 
 void NavDataCache::stampCacheFile(const SGPath& path)
 {
-  sqlite_bind_temp_stdstring(d->stampFileCache, 1, path.str());
+  sqlite_bind_temp_stdstring(d->stampFileCache, 1, path.utf8Str());
   sqlite3_bind_int64(d->stampFileCache, 2, path.modTime());
   d->execInsert(d->stampFileCache);
 }
@@ -2142,7 +2142,7 @@ NavDataCache::ThreadedGUISearch::ThreadedGUISearch(const std::string& term) :
 {
     SGPath p = NavDataCache::instance()->path();
     int openFlags = SQLITE_OPEN_READONLY;
-    std::string pathUtf8 = simgear::strutils::convertWindowsLocal8BitToUtf8(p.str());
+    std::string pathUtf8 = p.utf8Str();
     sqlite3_open_v2(pathUtf8.c_str(), &d->db, openFlags, NULL);
 
     std::string sql = "SELECT rowid FROM positioned WHERE name LIKE '%" + term
diff --git a/utils/GPSsmooth/GPSsmooth.cxx b/utils/GPSsmooth/GPSsmooth.cxx
index c3ddde99e..3196fa9f8 100644
--- a/utils/GPSsmooth/GPSsmooth.cxx
+++ b/utils/GPSsmooth/GPSsmooth.cxx
@@ -9,6 +9,7 @@
 #include <simgear/constants.h>
 #include <simgear/misc/sgstream.hxx>
 #include <simgear/misc/strutils.hxx>
+#include <simgear/misc/sg_path.hxx>
 
 #include "GPSsmooth.hxx"
 
@@ -27,7 +28,7 @@ int GPSTrack::load( const string &file ) {
     data.clear();
 
     // openg the file
-    sg_gzifstream in( file );
+    sg_gzifstream in( SGPath::fromLocal8Bit(file.c_str()) );
     if ( !in.is_open() ) {
         cout << "Cannot open file: " << file << endl;
         return 0;