diff --git a/simgear/ephemeris/ephemeris.cxx b/simgear/ephemeris/ephemeris.cxx
index a05481bd..f918c3f7 100644
--- a/simgear/ephemeris/ephemeris.cxx
+++ b/simgear/ephemeris/ephemeris.cxx
@@ -31,7 +31,7 @@
 
 
 // Constructor
-SGEphemeris::SGEphemeris( const std::string &path ) {
+SGEphemeris::SGEphemeris( const SGPath& path ) {
     our_sun = new Star;
     moon = new MoonPos;
     mercury = new Mercury;
@@ -44,7 +44,7 @@ SGEphemeris::SGEphemeris( const std::string &path ) {
     nplanets = 7;
     for ( int i = 0; i < nplanets; ++i )
       planets[i] = SGVec3d::zeros();
-    stars = new SGStarData( SGPath(path) );
+    stars = new SGStarData(path);
 }
 
 
diff --git a/simgear/ephemeris/ephemeris.hxx b/simgear/ephemeris/ephemeris.hxx
index 398eb3ef..abe5a8a0 100644
--- a/simgear/ephemeris/ephemeris.hxx
+++ b/simgear/ephemeris/ephemeris.hxx
@@ -97,7 +97,7 @@ public:
      * calling the constructor you need to provide a path pointing to
      * your star database file.
      * @param path path to your star database */
-    SGEphemeris( const std::string &path );
+    SGEphemeris( const SGPath &path );
 
     /** Destructor */
     ~SGEphemeris( void );
diff --git a/simgear/io/iostreams/sgstream.cxx b/simgear/io/iostreams/sgstream.cxx
index 77c30f1f..fc20e73a 100644
--- a/simgear/io/iostreams/sgstream.cxx
+++ b/simgear/io/iostreams/sgstream.cxx
@@ -212,7 +212,7 @@ sg_ifstream::sg_ifstream(const SGPath& path, ios_openmode io_mode)
 #if defined(SG_WINDOWS)
 	std::wstring ps = path.wstr();
 #else
-    std::string ps = path.local8BitStr();
+    std::string ps = path.utf8Str();
 #endif
 	std::ifstream::open(ps.c_str(), io_mode);
 }
@@ -222,7 +222,7 @@ void sg_ifstream::open( const SGPath& name, ios_openmode io_mode )
 #if defined(SG_WINDOWS)
 	std::wstring ps = name.wstr();
 #else
-	std::string ps = name.local8BitStr();
+	std::string ps = name.utf8Str();
 #endif
     std::ifstream::open(ps.c_str(), io_mode);
 }
@@ -232,7 +232,7 @@ sg_ofstream::sg_ofstream(const SGPath& path, ios_openmode io_mode)
 #if defined(SG_WINDOWS)
 	std::wstring ps = path.wstr();
 #else
-	std::string ps = path.local8BitStr();
+	std::string ps = path.utf8Str();
 #endif
     std::ofstream::open(ps.c_str(), io_mode);
 }
@@ -242,7 +242,7 @@ void sg_ofstream::open( const SGPath& name, ios_openmode io_mode )
 #if defined(SG_WINDOWS)
 	std::wstring ps = name.wstr();
 #else
-	std::string ps = name.local8BitStr();
+	std::string ps = name.utf8Str();
 #endif
     std::ofstream::open(ps.c_str(), io_mode);
 }
diff --git a/simgear/misc/path_test.cxx b/simgear/misc/path_test.cxx
old mode 100644
new mode 100755
index dac7c0d2..9ae36245
--- a/simgear/misc/path_test.cxx
+++ b/simgear/misc/path_test.cxx
@@ -333,6 +333,12 @@ void test_hash_function()
   SG_CHECK_NE(std::hash<SGPath>{}(p), std::hash<SGPath>{}(p / "foobar"));
 }
 
+void test_null_path()
+{
+	const SGPath nullPath;
+	SG_VERIFY(!nullPath.exists());
+}
+
 int main(int argc, char* argv[])
 {
     SGPath pa;
@@ -441,6 +447,7 @@ int main(int argc, char* argv[])
     test_update_dir();
     test_comparisons();
     test_hash_function();
+	test_null_path();
 
     cout << "all tests passed OK" << endl;
     return 0; // passed
diff --git a/simgear/misc/sg_dir.cxx b/simgear/misc/sg_dir.cxx
index 9430e1b2..0836a49b 100644
--- a/simgear/misc/sg_dir.cxx
+++ b/simgear/misc/sg_dir.cxx
@@ -115,7 +115,7 @@ Dir Dir::tempDir(const std::string& templ)
     // Mac OS-X / BSD manual says any number of 'X's, but GLibc manual
     // says exactly six, so that's what I'm going with
     p.concat("-XXXXXX");
-    std::string s = p.local8BitStr();
+    std::string s = p.utf8Str();
     ::snprintf(buf, 1024, "%s", s.c_str());
     if (!mkdtemp(buf)) {
         SG_LOG(SG_IO, SG_WARN,
@@ -206,7 +206,7 @@ PathList Dir::children(int types, const std::string& nameFilter) const
 
   FindClose(find);
 #else
-    std::string ps = _path.local8BitStr();
+    std::string ps = _path.utf8Str();
   DIR* dp = opendir(ps.c_str());
   if (!dp) {
     SG_LOG(SG_GENERAL, SG_WARN, "Dir::children: opendir failed:" << _path);
@@ -290,7 +290,7 @@ bool Dir::isEmpty() const
   std::wstring ps = _path.wstr();
   return PathIsDirectoryEmptyW( ps.c_str() );
 #else
-  std::string ps = _path.local8BitStr();
+  std::string ps = _path.utf8Str();
   DIR* dp = opendir( ps.c_str() );
   if (!dp) return true;
 
@@ -339,7 +339,7 @@ bool Dir::create(mode_t mode)
 	std::wstring ps = _path.wstr();
 	int err = _wmkdir(ps.c_str());
 #else
-    std::string ps = _path.local8BitStr();
+    std::string ps = _path.utf8Str();
     int err = mkdir(ps.c_str(), mode);
 #endif
     if (err) {
@@ -394,7 +394,7 @@ bool Dir::remove(bool recursive)
 	std::wstring ps = _path.wstr();
     int err = _wrmdir(ps.c_str());
 #else
-	std::string ps = _path.local8BitStr();
+	std::string ps = _path.utf8Str();
     int err = rmdir(ps.c_str());
 #endif
     if (err) {
diff --git a/simgear/misc/sg_path.cxx b/simgear/misc/sg_path.cxx
index 3d0e41b1..a252480f 100644
--- a/simgear/misc/sg_path.cxx
+++ b/simgear/misc/sg_path.cxx
@@ -786,8 +786,8 @@ bool SGPath::rename(const SGPath& newName)
 	std::wstring np = newName.wstr();
 	if (_wrename(p.c_str(), np.c_str()) != 0)
 #else
-    std::string p = local8BitStr();
-    std::string np = newName.local8BitStr();
+    std::string p = utf8Str();
+    std::string np = newName.utf8Str();
     if( ::rename(p.c_str(), np.c_str()) != 0 )
 #endif
 
diff --git a/simgear/scene/material/mat.cxx b/simgear/scene/material/mat.cxx
index 1ebb86b1..6bedbdcd 100644
--- a/simgear/scene/material/mat.cxx
+++ b/simgear/scene/material/mat.cxx
@@ -149,7 +149,7 @@ SGMaterial::read_properties(const SGReaderWriterOptions* options,
 
         SGPath tpath("Textures");
         tpath.append(tname);
-        std::string fullTexPath = SGModelLib::findDataFile(tpath.local8BitStr(), options);
+        std::string fullTexPath = SGModelLib::findDataFile(tpath, options);
         if (fullTexPath.empty()) {
             SG_LOG(SG_GENERAL, SG_ALERT, "Cannot find texture \""
                     << tname << "\" in Textures folders.");
@@ -181,7 +181,7 @@ SGMaterial::read_properties(const SGReaderWriterOptions* options,
 
             SGPath tpath("Textures");
             tpath.append(tname);
-            std::string fullTexPath = SGModelLib::findDataFile(tpath.local8BitStr(), options);
+            std::string fullTexPath = SGModelLib::findDataFile(tpath, options);
             if (fullTexPath.empty()) {
                 SG_LOG(SG_GENERAL, SG_ALERT, "Cannot find texture \""
                         << tname << "\" in Textures folders.");
@@ -207,7 +207,7 @@ SGMaterial::read_properties(const SGReaderWriterOptions* options,
         SGPath tpath("Textures");
         tpath.append("Terrain");
         tpath.append("unknown.rgb");
-        _internal_state st( NULL, tpath.local8BitStr(), true, options );
+        _internal_state st( NULL, tpath.utf8Str(), true, options );
         _status.push_back( st );
     }
 
@@ -219,7 +219,7 @@ SGMaterial::read_properties(const SGReaderWriterOptions* options,
         if (! omname.empty()) {
             SGPath ompath("Textures");
             ompath.append(omname);
-            std::string fullMaskPath = SGModelLib::findDataFile(ompath.local8BitStr(), options);
+            std::string fullMaskPath = SGModelLib::findDataFile(ompath, options);
 
             if (fullMaskPath.empty()) {
                 SG_LOG(SG_GENERAL, SG_ALERT, "Cannot find texture \""
@@ -358,7 +358,7 @@ SGMaterial::read_properties(const SGReaderWriterOptions* options,
         if (! treeTexPath.empty()) {
             SGPath treePath("Textures");
             treePath.append(treeTexPath);
-            tree_texture = SGModelLib::findDataFile(treePath.local8BitStr(), options);
+            tree_texture = SGModelLib::findDataFile(treePath, options);
 
             if (tree_texture.empty()) {
                 SG_LOG(SG_GENERAL, SG_ALERT, "Cannot find texture \""
diff --git a/simgear/scene/material/matlib.cxx b/simgear/scene/material/matlib.cxx
index 0b40869d..3459d7e0 100644
--- a/simgear/scene/material/matlib.cxx
+++ b/simgear/scene/material/matlib.cxx
@@ -65,7 +65,7 @@ SGMaterialLib::SGMaterialLib ( void ) :
 }
 
 // Load a library of material properties
-bool SGMaterialLib::load( const string &fg_root, const string& mpath,
+bool SGMaterialLib::load( const SGPath &fg_root, const SGPath& mpath,
         SGPropertyNode *prop_root )
 {
     SGPropertyNode materialblocks;
@@ -81,7 +81,7 @@ bool SGMaterialLib::load( const string &fg_root, const string& mpath,
     osg::ref_ptr<osgDB::Options> options
         = new osgDB::Options;
     options->setObjectCacheHint(osgDB::Options::CACHE_ALL);
-    options->setDatabasePath(fg_root);
+    options->setDatabasePath(fg_root.utf8Str());
 
     simgear::PropertyList blocks = materialblocks.getChildren("region");
     simgear::PropertyList::const_iterator block_iter = blocks.begin();
diff --git a/simgear/scene/material/matlib.hxx b/simgear/scene/material/matlib.hxx
index 90fb273c..ff80d795 100644
--- a/simgear/scene/material/matlib.hxx
+++ b/simgear/scene/material/matlib.hxx
@@ -38,6 +38,7 @@
 
 class SGMaterial;
 class SGPropertyNode;
+class SGPath;
 
 namespace simgear { class Effect; }
 namespace osg { class Geode; }
@@ -87,7 +88,7 @@ public:
     SGMaterialLib ( void );
 
     // Load a library of material properties
-    bool load( const std::string &fg_root, const std::string& mpath,
+    bool load( const SGPath &fg_root, const SGPath& mpath,
             SGPropertyNode *prop_root );
     // find a material record by material name
     SGMaterial *find( const std::string& material, SGVec2f center ) const;
diff --git a/simgear/scene/model/SGReaderWriterXML.cxx b/simgear/scene/model/SGReaderWriterXML.cxx
index b6fc37e9..adb86e41 100644
--- a/simgear/scene/model/SGReaderWriterXML.cxx
+++ b/simgear/scene/model/SGReaderWriterXML.cxx
@@ -338,12 +338,12 @@ sgLoad3DModel_internal(const SGPath& path,
         if (!texturepath.extension().empty())
             texturepath = texturepath.dir();
 
-        options->setDatabasePath(texturepath.local8BitStr());
+        options->setDatabasePath(texturepath.utf8Str());
         osgDB::ReaderWriter::ReadResult modelResult;
 #if OSG_VERSION_LESS_THAN(3,4,1)
-        modelResult = osgDB::readNodeFile(modelpath.local8BitStr(), options.get());
+        modelResult = osgDB::readNodeFile(modelpath.utf8Str(), options.get());
 #else
-        modelResult = osgDB::readRefNodeFile(modelpath.local8BitStr(), options.get());
+        modelResult = osgDB::readRefNodeFile(modelpath.utf8Str(), options.get());
 #endif
         if (!modelResult.validNode())
             throw sg_io_exception("Failed to load 3D model:" + modelResult.message(),
@@ -503,7 +503,7 @@ sgLoad3DModel_internal(const SGPath& path,
                 if (!texturepath.extension().empty())
                     texturepath = texturepath.dir();
 
-                options2->setDatabasePath(texturepath.local8BitStr());
+                options2->setDatabasePath(texturepath.utf8Str());
             }
             group->addChild(Particles::appendParticles(particle_nodes[i],
                                                        prop_root,
@@ -544,7 +544,7 @@ sgLoad3DModel_internal(const SGPath& path,
         group = static_cast<Group*>(modelWithEffects.get());
     }
 
-    simgear::SGTransientModelData modelData(group.get(), prop_root, options.get(), path.local8BitStr());
+    simgear::SGTransientModelData modelData(group.get(), prop_root, options.get(), path.utf8Str());
 
     for (unsigned i = 0; i < animation_nodes.size(); ++i) {
         if (previewMode && animation_nodes[i]->hasChild("nopreview")) {
diff --git a/simgear/scene/model/SGText.cxx b/simgear/scene/model/SGText.cxx
index 62081f13..d47b5337 100644
--- a/simgear/scene/model/SGText.cxx
+++ b/simgear/scene/model/SGText.cxx
@@ -97,7 +97,7 @@ osg::Node * SGText::appendText(const SGPropertyNode* configNode,
 
   SGPath path("Fonts" );
   path.append( configNode->getStringValue( "font", "Helvetica" ));
-  text->setFont( path.local8BitStr() );
+  text->setFont( path.utf8Str() );
 
   text->setCharacterSize(configNode->getDoubleValue("character-size", 1.0 ), 
                          configNode->getDoubleValue("character-aspect-ratio", 1.0 ));
diff --git a/simgear/scene/model/model.hxx b/simgear/scene/model/model.hxx
index 956d329b..4e719527 100644
--- a/simgear/scene/model/model.hxx
+++ b/simgear/scene/model/model.hxx
@@ -47,7 +47,7 @@ SGLoadTexture2D(const SGPath& path,
                 bool wrapu = true, bool wrapv = true,
                 int mipmaplevels = -1)
 {
-    return SGLoadTexture2D(true, path.local8BitStr(), options, wrapu, wrapv,
+    return SGLoadTexture2D(true, path.utf8Str(), options, wrapu, wrapv,
                            mipmaplevels);
 }
 
@@ -57,7 +57,7 @@ SGLoadTexture2D(bool staticTexture, const SGPath& path,
                 bool wrapu = true, bool wrapv = true,
                 int mipmaplevels = -1)
 {
-    return SGLoadTexture2D(staticTexture, path.local8BitStr(), options, wrapu, wrapv,
+    return SGLoadTexture2D(staticTexture, path.utf8Str(), options, wrapu, wrapv,
                            mipmaplevels);
 }
 
diff --git a/simgear/scene/model/modellib.cxx b/simgear/scene/model/modellib.cxx
index 92b19196..1dd32459 100644
--- a/simgear/scene/model/modellib.cxx
+++ b/simgear/scene/model/modellib.cxx
@@ -77,13 +77,27 @@ std::string SGModelLib::findDataFile(const std::string& file,
     return file;
   SGPath p = ResourceManager::instance()->findPath(file, currentPath);
   if (p.exists()) {
-    return p.local8BitStr();
+    return p.utf8Str();
   }
 
   // finally hand on to standard OSG behaviour
   return osgDB::findDataFile(file, opts);
 }
 
+std::string SGModelLib::findDataFile(const SGPath& file,
+  const osgDB::Options* opts,
+  SGPath currentPath)
+{
+  SGPath p = ResourceManager::instance()->findPath(file.utf8Str(), currentPath);
+  if (p.exists()) {
+    return p.utf8Str();
+  }
+
+  // finally hand on to standard OSG behaviour
+  return osgDB::findDataFile(file.utf8Str(), opts);
+}
+
+
 SGModelLib::SGModelLib()
 {
 }
diff --git a/simgear/scene/model/modellib.hxx b/simgear/scene/model/modellib.hxx
index b9be0311..6032bb1e 100644
--- a/simgear/scene/model/modellib.hxx
+++ b/simgear/scene/model/modellib.hxx
@@ -85,7 +85,11 @@ public:
                                     SGModelData *data=0);
 
     static std::string findDataFile(const std::string& file,
-      const osgDB::Options* opts = NULL,
+      const osgDB::Options* opts = nullptr,
+      SGPath currentDir = SGPath());
+
+    static std::string findDataFile(const SGPath& file,
+      const osgDB::Options* opts = nullptr,
       SGPath currentDir = SGPath());
 protected:
     SGModelLib();
diff --git a/simgear/scene/sky/cloud.cxx b/simgear/scene/sky/cloud.cxx
index 89a964b7..103f7e4e 100644
--- a/simgear/scene/sky/cloud.cxx
+++ b/simgear/scene/sky/cloud.cxx
@@ -78,7 +78,7 @@ SGMakeState(const SGPath &path, const char* colorTexture,
     osg::StateSet *stateSet = new osg::StateSet;
 
     osg::ref_ptr<SGReaderWriterOptions> options;
-    options = SGReaderWriterOptions::fromPath(path.local8BitStr());
+    options = SGReaderWriterOptions::fromPath(path);
     stateSet->setTextureAttribute(0, SGLoadTexture2D(colorTexture,
                                                      options.get()));
     stateSet->setTextureMode(0, GL_TEXTURE_2D, osg::StateAttribute::ON);
diff --git a/simgear/scene/sky/moon.cxx b/simgear/scene/sky/moon.cxx
index 7f7412d1..d9a1e39c 100644
--- a/simgear/scene/sky/moon.cxx
+++ b/simgear/scene/sky/moon.cxx
@@ -76,7 +76,7 @@ SGMoon::build( SGPath path, double moon_size ) {
 
     // set up the orb state
     osg::ref_ptr<SGReaderWriterOptions> options;
-    options = SGReaderWriterOptions::fromPath(path.local8BitStr());
+    options = SGReaderWriterOptions::fromPath(path);
 
     osg::Texture2D* texture = SGLoadTexture2D("moon.png", options.get());
     stateSet->setTextureAttributeAndModes(0, texture, osg::StateAttribute::ON);
diff --git a/simgear/scene/sky/newcloud.cxx b/simgear/scene/sky/newcloud.cxx
index 8e9eb714..96437427 100644
--- a/simgear/scene/sky/newcloud.cxx
+++ b/simgear/scene/sky/newcloud.cxx
@@ -118,7 +118,7 @@ SGNewCloud::SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def
                            "image"),
                  texture);
         ref_ptr<SGReaderWriterOptions> options;
-        options = SGReaderWriterOptions::fromPath(texture_root.local8BitStr());
+        options = SGReaderWriterOptions::fromPath(texture_root);
         effect = makeEffect(pcloudEffect, true, options.get());
         if (effect.valid())
         {
diff --git a/simgear/scene/sky/oursun.cxx b/simgear/scene/sky/oursun.cxx
index 1e856f64..43d3e3b2 100644
--- a/simgear/scene/sky/oursun.cxx
+++ b/simgear/scene/sky/oursun.cxx
@@ -70,7 +70,7 @@ SGSun::build( SGPath path, double sun_size, SGPropertyNode *property_tree_Node )
     env_node = property_tree_Node;
 
     osg::ref_ptr<SGReaderWriterOptions> options;
-    options = SGReaderWriterOptions::fromPath(path.local8BitStr());
+    options = SGReaderWriterOptions::fromPath(path);
     // build the ssg scene graph sub tree for the sky and connected
     // into the provide scene graph branch
     sun_transform = new osg::MatrixTransform;
diff --git a/simgear/scene/tgdb/ReaderWriterSTG.cxx b/simgear/scene/tgdb/ReaderWriterSTG.cxx
index 73fc9da0..9aff6737 100644
--- a/simgear/scene/tgdb/ReaderWriterSTG.cxx
+++ b/simgear/scene/tgdb/ReaderWriterSTG.cxx
@@ -276,7 +276,7 @@ struct ReaderWriterSTG::_ModelBin {
 
         SGPath path = filePath;
         path.append(".."); path.append(".."); path.append("..");
-        sharedOptions->getDatabasePathList().push_back(path.local8BitStr());
+        sharedOptions->getDatabasePathList().push_back(path.utf8Str());
 
         // ensure Models directory synced via TerraSync is searched before the copy in
         // FG_ROOT, so that updated models can be used.
@@ -372,7 +372,7 @@ struct ReaderWriterSTG::_ModelBin {
 
         SG_LOG(SG_TERRAIN, SG_INFO, "Loading stg file " << absoluteFileName);
 
-        std::string filePath = osgDB::getFilePath(absoluteFileName.local8BitStr());
+        std::string filePath = osgDB::getFilePath(absoluteFileName.utf8Str());
 
         // Bucket provides a consistent seed
         // so we have consistent set of pseudo-random numbers for each STG file
@@ -420,7 +420,7 @@ struct ReaderWriterSTG::_ModelBin {
                     _Object obj;
                     obj._errorLocation = absoluteFileName;
                     obj._token = token;
-                    obj._name = path.local8BitStr();
+                    obj._name = path.utf8Str();
                     obj._options = staticOptions(filePath, options);
                     _objectList.push_back(obj);
                 }
@@ -430,7 +430,7 @@ struct ReaderWriterSTG::_ModelBin {
                     _Object obj;
                     obj._errorLocation = absoluteFileName;
                     obj._token = token;
-                    obj._name = path.local8BitStr();
+                    obj._name = path.utf8Str();
                     obj._options = staticOptions(filePath, options);
                     _objectList.push_back(obj);
                 }
@@ -537,7 +537,7 @@ struct ReaderWriterSTG::_ModelBin {
                     _objectStaticList.push_back(obj);
                 } else if (token == BUILDING_LIST) {
                   _BuildingList buildinglist;
-                  buildinglist._filename = path.local8BitStr();
+                  buildinglist._filename = path.utf8Str();
                   in >> buildinglist._material_name >> buildinglist._lon >> buildinglist._lat >> buildinglist._elev;
                   checkInsideBucket(absoluteFileName, buildinglist._lon, buildinglist._lat);
                   _buildingListList.push_back(buildinglist);
diff --git a/simgear/scene/util/SGReaderWriterOptions.cxx b/simgear/scene/util/SGReaderWriterOptions.cxx
index 12e32128..8937bd42 100644
--- a/simgear/scene/util/SGReaderWriterOptions.cxx
+++ b/simgear/scene/util/SGReaderWriterOptions.cxx
@@ -47,10 +47,10 @@ SGReaderWriterOptions::copyOrCreate(const osgDB::Options* options)
 }
 
 SGReaderWriterOptions*
-SGReaderWriterOptions::fromPath(const std::string& path)
+SGReaderWriterOptions::fromPath(const SGPath& path)
 {
-    SGReaderWriterOptions* options = copyOrCreate(0);
-    options->setDatabasePath(path);
+    SGReaderWriterOptions* options = copyOrCreate(nullptr);
+    options->setDatabasePath(path.utf8Str());
     return options;
 }
 
diff --git a/simgear/scene/util/SGReaderWriterOptions.hxx b/simgear/scene/util/SGReaderWriterOptions.hxx
index 17183944..940dd761 100644
--- a/simgear/scene/util/SGReaderWriterOptions.hxx
+++ b/simgear/scene/util/SGReaderWriterOptions.hxx
@@ -31,6 +31,8 @@
 #endif
 
 class SGPropertyNode;
+class SGPath;
+
 typedef std::vector < std::string > string_list;
 
 namespace simgear
@@ -50,7 +52,6 @@ public:
     SGReaderWriterOptions() :
         _materialLib(0),
         _load_panel(0),
-        _model_data(0),
         _instantiateEffects(false),
         _instantiateMaterialEffects(false),
         _LoadOriginHint(ORIGIN_MODEL)
@@ -59,7 +60,6 @@ public:
         osgDB::Options(str),
         _materialLib(0),
         _load_panel(0),
-        _model_data(0),
         _instantiateEffects(false),
         _instantiateMaterialEffects(false),
         _LoadOriginHint(ORIGIN_MODEL)
@@ -69,7 +69,6 @@ public:
         osgDB::Options(options, copyop),
         _materialLib(0),
         _load_panel(0),
-        _model_data(0),
         _instantiateEffects(false),
         _instantiateMaterialEffects(false),
         _LoadOriginHint(ORIGIN_MODEL)
@@ -144,7 +143,7 @@ public:
     { _sceneryPathSuffixes = suffixes; }
 
     static SGReaderWriterOptions* copyOrCreate(const osgDB::Options* options);
-    static SGReaderWriterOptions* fromPath(const std::string& path);
+    static SGReaderWriterOptions* fromPath(const SGPath& path);
 
     void setLocation(double lon, double lat)
     { _geod = SGGeod::fromDeg(lon, lat); }
diff --git a/simgear/timing/sg_time.cxx b/simgear/timing/sg_time.cxx
index 83b22aec..dc8b6ac0 100644
--- a/simgear/timing/sg_time.cxx
+++ b/simgear/timing/sg_time.cxx
@@ -222,7 +222,7 @@ void SGTime::update( const SGGeod& location, time_t ct, long int warp )
 
 
 // Given lon/lat, update timezone information and local_offset
-void SGTime::updateLocal( const SGGeod& aLocation, const string& root ) {
+void SGTime::updateLocal( const SGGeod& aLocation, const SGPath& root ) {
   SGGeod location(aLocation);
     if (!aLocation.isValid()) {
         location = SGGeod();
diff --git a/simgear/timing/sg_time.hxx b/simgear/timing/sg_time.hxx
index 00c058af..0990d0e2 100644
--- a/simgear/timing/sg_time.hxx
+++ b/simgear/timing/sg_time.hxx
@@ -162,7 +162,7 @@ public:
      * @param location  Current geodetic location
      * @param root      Bbase path containing time zone directory
      */
-    void updateLocal( const SGGeod& location, const std::string& root );
+    void updateLocal( const SGGeod& location, const SGPath& root );
 
     /** @return current system/unix time in seconds */
     inline time_t get_cur_time() const { return cur_time; };