diff -r e183e3b3a041 configure.ac
--- a/configure.ac	Tue Sep 06 22:12:05 2016 -0700
+++ b/configure.ac	Sat Mar 18 05:09:04 2017 +0100
@@ -10,6 +10,8 @@
 AC_PREREQ(2.52)
 AM_INIT_AUTOMAKE
 
+CXXFLAGS="-std=c++11"
+
 dnl Checks for programs.
 AC_PROG_MAKE_SET
 AC_PROG_CC
diff -r e183e3b3a041 src/FlightTrack.cxx
--- a/src/FlightTrack.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/FlightTrack.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -81,7 +81,7 @@
 	throw runtime_error("flight file open failure");
     }
 
-    _file.set(filePath);
+    _file = SGPath(filePath);
 
     _port = -1;
     _device = "";
@@ -101,7 +101,7 @@
     _input_channel = new SGSocket("", portStr.str(), "udp");
     _input_channel->open(SG_IO_IN);
 
-    _file.set("");
+    _file = SGPath();
 
     _port = port;
     _device = "";
@@ -123,7 +123,7 @@
     _input_channel = new SGSerial(device, baudStr.str());
     _input_channel->open(SG_IO_IN);
 
-    _file.set("");
+    _file = SGPath();
 
     _port = -1;
     _device = device;
@@ -399,11 +399,11 @@
     return _name.str();
 }
 
-void FlightTrack::setFilePath(char *path)
+void FlightTrack::setFilePath(const char *path)
 {
     // EYE - check for existing name?  overwriting?
     // EYE - call this (and other accessors) from constructors?
-    _file.set(path);
+    _file = SGPath(path);
     // We count this as a change.
     _version++;
     _versionAtLastSave = 0;
diff -r e183e3b3a041 src/FlightTrack.hxx
--- a/src/FlightTrack.hxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/FlightTrack.hxx	Sat Mar 18 05:09:04 2017 +0100
@@ -141,7 +141,7 @@
     const char *fileName();	// File name
     const char *filePath();	// Full path, including file
     const char *niceName();	// Nicely formatted name
-    void setFilePath(char *path);
+    void setFilePath(const char *path);
     void save();
     bool modified();
 
diff -r e183e3b3a041 src/Geographics.cxx
--- a/src/Geographics.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/Geographics.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -25,6 +25,7 @@
 #include "Geographics.hxx"
 
 // C++ system files
+#include <cmath>
 #include <stdexcept>
 
 // Our project's include files
@@ -431,11 +432,11 @@
 bool AtlasCoord::_geodValid() const
 {
     // Note: this has to agree with the value set in invalidate()!
-    return !isnan(_geod.getLatitudeDeg());
+    return !std::isnan(_geod.getLatitudeDeg());
 }
 
 bool AtlasCoord::_cartValid() const
 {
     // Note: this has to agree with the value set in invalidate()!
-    return !isnan(_cart.x());
+    return !std::isnan(_cart.x());
 }
diff -r e183e3b3a041 src/Map.cxx
--- a/src/Map.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/Map.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -168,13 +168,13 @@
 bool parse_arg(char* arg) 
 {
     if (strncmp(arg, "--fg-root=", 10) == 0) {
-	fg_root.set(arg + 10);
+	fg_root = SGPath(arg + 10);
     } else if (strncmp(arg, "--fg-scenery=", 13) == 0) {
-	scenery.set(arg + 13);
+	scenery = SGPath(arg + 13);
     } else if (strncmp(arg, "--atlas=", 8) == 0) {
-	atlas.set(arg + 8);
+	atlas = SGPath(arg + 8);
     } else if (strncmp(arg, "--palette=", 10) == 0) {
-	palette.set(arg + 10);
+	palette = SGPath(arg + 10);
     } else if (strcmp(arg, "--png") == 0) {
 	imageType = TileMapper::PNG;
     } else if (strcmp(arg, "--jpeg") == 0) {
@@ -272,23 +272,14 @@
     // Read the FG_ROOT and FG_SCENERY environment variables before
     // processing .atlasmaprc and command args, so that we can
     // override them if necessary.
-    char *env = getenv("FG_ROOT");
-    if (env == NULL) {
-	// EYE - is it possible for this to not be defined?
-	fg_root.set(FGBASE_DIR);
-    } else {
-	fg_root.set(env);
-    }
 
-    env = getenv("FG_SCENERY");
-    if (env == NULL) {
-	fg_scenery.set(fg_root.str() + "/Scenery");
-    } else {
-	fg_scenery.set(env);
-    }
+    // EYE - is it possible for this to not be defined?
+    fg_root = SGPath::fromEnv("FG_ROOT", SGPath(FGBASE_DIR));
+
+    fg_scenery = SGPath::fromEnv("FG_SCENERY", fg_root.str() + "/Scenery");
 
     // Set a default palette.
-    palette.set("default.ap");
+    palette = SGPath("default.ap");
 
     // Process ~/.atlasmaprc.
     char* homedir = getenv("HOME");
@@ -332,10 +323,10 @@
 	// 'scenery'.  We're done.
     } else if (!fg_scenery.str().empty()) {
 	// From FG_SCENERY
-	scenery.set(fg_scenery.str());
+	scenery = SGPath(fg_scenery.str());
     } else if (!fg_root.str().empty()) {
 	// Default: $FG_ROOT/Scenery
-	scenery.set(fg_root.str());
+	scenery = SGPath(fg_root.str());
 	scenery.append("Scenery");
     } else {
 	fprintf(stderr, "%s: No scenery directory specified.", appName);
@@ -356,7 +347,7 @@
     } else if (!fg_root.str().empty()) {
 	// EYE - make default $HOME/Atlas?
 	// Default: $FG_ROOT/Atlas
-	atlas.set(fg_root.str());
+	atlas = SGPath(fg_root.str());
 	atlas.append("Atlas");
     } else {
 	fprintf(stderr, "%s: No map directory specified.", appName);
@@ -394,11 +385,11 @@
     SGPath palettePath;
     palettePath.append(palette.str());
     if ((atlasPalette = loadPalette(palettePath.c_str())) == NULL) {
-	palettePath.set(atlas.str());
+	palettePath = SGPath(atlas.str());
 	palettePath.append("Palettes");
 	palettePath.append(palette.str());
 	if ((atlasPalette = loadPalette(palettePath.c_str())) == NULL) {
-	    palettePath.set(fg_root.str());
+	    palettePath = SGPath(fg_root.str());
 	    palettePath.append("Atlas");
 	    palettePath.append("Palettes");
 	    palettePath.append(palette.str());
diff -r e183e3b3a041 src/Preferences.cxx
--- a/src/Preferences.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/Preferences.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -317,7 +317,7 @@
 {
     string buf;
     is >> buf;
-    p.set(buf);
+    p = SGPath(buf);
 
     return is;
 }
@@ -638,7 +638,7 @@
     // EYE - just get()?
     SGPath p(fg_root.get(Pref::FACTORY));
     if (p.isNull()) {
-	p.set(FGBASE_DIR);
+	p = SGPath(FGBASE_DIR);
     }
     p.append("Atlas");
     path.set(p, Pref::FACTORY);
@@ -770,10 +770,10 @@
     char* homedir = getenv("HOME");
     SGPath rcpath;
     if (homedir != NULL) {
-	rcpath.set(homedir);
+	rcpath = SGPath(homedir);
 	rcpath.append(atlasrc);
     } else {
-	rcpath.set(atlasrc);
+	rcpath = SGPath(atlasrc);
     }
 
     ifstream rc(rcpath.c_str());
@@ -946,7 +946,7 @@
     }
     SGPath p;
     while (optind < argc) {
-	p.set(argv[optind++]);
+	p = SGPath(argv[optind++]);
 	flightFiles.push_back(p);
     }
 
diff -r e183e3b3a041 src/Scenery.cxx
--- a/src/Scenery.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/Scenery.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -198,7 +198,7 @@
 	data = (GLubyte *)loadJPEG(f.c_str(), &width, &height, &depth, 
 				   maximumElevation);
 	if (!data) {
-	    f.set(f.base());
+	    f = SGPath(f.base());
 	    f.concat(".png");
 	    data = (GLubyte *)loadPNG(f.c_str(), &width, &height, &depth,
 				      maximumElevation);
diff -r e183e3b3a041 src/Subbucket.cxx
--- a/src/Subbucket.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/Subbucket.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -346,10 +346,10 @@
     // http://wiki.flightgear.org/index.php/BTG_File_Format
 
     SGBinObject btg;
-    if (!btg.read_bin(_path.c_str())) {
-	// EYE - throw an error?
-	// EYE - will the cache continue to call load() then?
-	return false;
+    if (!btg.read_bin(SGPath(_path))) {
+        // EYE - throw an error?
+        // EYE - will the cache continue to call load() then?
+        return false;
     }
 
     //////////////////////////////////////////////////////////////////////
diff -r e183e3b3a041 src/Tiles.cxx
--- a/src/Tiles.cxx	Tue Sep 06 22:12:05 2016 -0700
+++ b/src/Tiles.cxx	Sat Mar 18 05:09:04 2017 +0100
@@ -464,7 +464,7 @@
 const SGPath& TileManager::mapPath(unsigned int level)
 {
     static SGPath result;
-    result.set(_maps.str());
+    result = SGPath(_maps.str());
 
     char str[3];
     snprintf(str, 3, "%d", level);
@@ -821,7 +821,7 @@
 const SGPath& Tile::sceneryDir()
 {
     if (_sceneryIndex == TileManager::NaPI) {
-	__sceneryPath = "";
+	__sceneryPath = SGPath();
     } else {
 	__sceneryPath = _tm->sceneryPaths()[_sceneryIndex];
 	__sceneryPath.append(chunk()->name());