BUG: Mantis-1289 : Clear and update DEM loading data to update pixels parameters.

Put DEM clear and loading in DoUpdate().
This change correct a side effect that was present in DoExecute() function.

Modules/Applications/AppProjection/app/otbOrthoRectification.cxx

@@ -235,6 +235,11 @@ private:
   {
     if (HasValue("io.in"))
       {
+
+      // Clear and reset the DEM Handler
+      otb::DEMHandler::Instance()->ClearDEMs();
+      otb::Wrapper::ElevationParametersHandler::SetupDEMHandlerFromElevationParameters(this,"elev");
+
       // input image
       FloatVectorImageType::Pointer inImage = GetParameterImage("io.in");
 
@@ -645,9 +650,6 @@ private:
       break;
       }
 
-    // Setup the DEM Handler
-    otb::Wrapper::ElevationParametersHandler::SetupDEMHandlerFromElevationParameters(this,"elev");
-
     // If activated, generate RPC model
     if(IsParameterEnabled("opt.rpc"))
       {

Modules/Wrappers/ApplicationEngine/src/otbWrapperElevationParametersHandler.cxx

@@ -107,10 +107,20 @@ void ElevationParametersHandler::SetupDEMHandlerFromElevationParameters(const Ap
   // Set DEM directory if available
   if(IsDEMUsed(app,key))
     {
-    oss.str("");
-    oss<<"Elevation management: using DEM directory ("<<GetDEMDirectory(app,key)<<")"<<std::endl;
-    otb::DEMHandler::Instance()->OpenDEMDirectory(GetDEMDirectory(app,key));
-    app->GetLogger()->Info(oss.str());
+    std::string demDirectory = GetDEMDirectory(app,key);
+    if(otb::DEMHandler::Instance()->IsValidDEMDirectory(demDirectory.c_str()))
+      {
+      oss.str( "" );
+      oss << "Elevation management: using DEM directory (" << demDirectory << ")" << std::endl;
+      otb::DEMHandler::Instance()->OpenDEMDirectory( demDirectory );
+      app->GetLogger()->Info( oss.str() );
+      }
+    else
+      {
+      oss.str( "" );
+      oss << "DEM directory : " << demDirectory << " is not a valid DEM directory";
+      app->GetLogger()->Warning( oss.str() );
+      }
     }
 }
 
@@ -161,10 +171,10 @@ ElevationParametersHandler::IsGeoidUsed(const Application::Pointer app, const st
 bool
 ElevationParametersHandler::IsDEMUsed(const Application::Pointer app, const std::string& key)
 {
-  std::ostringstream geoidKey;
-  geoidKey<< key<<".dem";
+  std::ostringstream demKey;
+  demKey<< key<<".dem";
 
-  return app->IsParameterEnabled(geoidKey.str()) && app->HasValue(geoidKey.str());
+  return app->IsParameterEnabled(demKey.str()) && app->HasValue(demKey.str());
 }