ENH: add a method to get the activity status of the group elevation

Code/ApplicationEngine/otbWrapperElevationParametersHandler.cxx

@@ -28,6 +28,7 @@ void ElevationParametersHandler::AddElevationParameters(Application::Pointer app
   app->AddParameter(ParameterType_Choice, key, "Elevation management");
   app->SetParameterDescription(key,
                                "This group of parameters allows to manage elevation values. Supported formats are SRTM, DTED or any geotiff processed by the DEM import application");
+  app->MandatoryOff(key);
 
   // DEM directory
   std::ostringstream oss;
@@ -143,5 +144,11 @@ ElevationParametersHandler::IsGeoidUsed(const Application::Pointer app, const st
   return app->IsParameterEnabled(geoidKey.str()) && app->HasValue(geoidKey.str());
 }
 
+bool 
+ElevationParametersHandler::IsElevationEnabled(const Application::Pointer app, const std::string & key)
+{
+  return app->IsParameterEnabled(key);
+}
+
 }// End namespace Wrapper
 }// End namespace otb

Code/ApplicationEngine/otbWrapperElevationParametersHandler.h

@@ -59,6 +59,7 @@ public:
   static float GetAverageElevation(const Application::Pointer app, const std::string& key);
   static const std::string GetGeoidFile(const Application::Pointer app, const std::string& key);
   static bool IsGeoidUsed(const Application::Pointer app, const std::string& key);
+  static bool IsElevationEnabled(const Application::Pointer app, const std::string & key);
 
 protected:
   ElevationParametersHandler(); // not implemented