diff --git a/simgear/scene/tgdb/ReaderWriterSTG.cxx b/simgear/scene/tgdb/ReaderWriterSTG.cxx
index 386a3f6..1f126f3 100644
--- a/simgear/scene/tgdb/ReaderWriterSTG.cxx
+++ b/simgear/scene/tgdb/ReaderWriterSTG.cxx
@@ -46,6 +46,9 @@

 #include "SGOceanTile.hxx"

+#include <boost/regex.hpp>
+
+
 using namespace simgear;

 static SGBucket bucketIndexFromFileName(const std::string& fileName)
@@ -73,6 +76,16 @@ static bool hasOptionalValue(sg_gzifstream &in)
     }
 }

+static double getGroundElevation(double &lon, double &lat, std::string &offset)
+{
+    double GroundElevation(666.45);
+    SG_LOG( SG_TERRAIN, SG_ALERT, "Compute ground elevation for STG object with lon="<< lon <<" and lat=" << lat << " with offset="<< offset);
+    //SGGeod geod = SGGeod::fromDegM(lon, lat, "10000");
+    //here we need to find a SimGear function who return the ground elevation with lon/lat parameters
+
+    return GroundElevation;
+}
+
 ReaderWriterSTG::ReaderWriterSTG()
 {
     supportsExtension("stg", "SimGear stg database format");
@@ -240,8 +253,29 @@ ReaderWriterSTG::readStgFile(const std::string& absoluteFileName,
             }

         } else {
+           boost::regex re("(GND)([\\+-]{1}[0-9.]+)?");
+           boost::cmatch matches;
+           std::string gnd;
             double lon, lat, elev, hdg;
-            in >> lon >> lat >> elev >> hdg;
+
+            in >> lon >> lat >> gnd >> hdg;
+
+
+           if ( boost::regex_match(gnd.c_str(), matches, re) ) {
+
+               //for ( int i = 1; i < matches.size(); i++) {
+                   string match(matches[2].first, matches[2].second);
+                 //  cout << "\tmatches[" << i << "] = " << match << endl;
+
+                    SG_LOG( SG_TERRAIN, SG_ALERT, absoluteFileName << ": GND Regex detected '" << name << "' Offset=" << match);
+                   elev = getGroundElevation(lon, lat, match);
+               //}
+
+            } else {
+
+               elev = atof(gnd.c_str());
+
+            }

             // Always OK to load
             if ( token == "OBJECT_STATIC" ) {