ENH: Force forward relations only when inverted mode is disabled

Code/SpatialReasoning/otbPolygonListToRCC8GraphFilter.txx

@@ -341,7 +341,18 @@ PolygonListToRCC8GraphFilter<TPolygonList, TOutputGraph>
           {
             // Add the edge to the graph.
             otbMsgDevMacro(<<"Adding edge: "<<vIt1.GetIndex()<<" -> "<<vIt2.GetIndex()<<": "<<value);
-            m_EdgesPerThread[threadId][EdgePairType(vIt1.GetIndex(),vIt2.GetIndex())]=value;
+	    if(value==OTB_RCC8_NTPPI)
+	      {
+	      m_EdgesPerThread[threadId][EdgePairType(vIt2.GetIndex(),vIt1.GetIndex())]=OTB_RCC8_NTPP;
+	      }
+	    else if(value == OTB_RCC8_TPPI)
+	      {
+	      m_EdgesPerThread[threadId][EdgePairType(vIt2.GetIndex(),vIt1.GetIndex())]=OTB_RCC8_TPP;
+	      }
+	    else
+	      {
+	      m_EdgesPerThread[threadId][EdgePairType(vIt1.GetIndex(),vIt2.GetIndex())]=value;
+	      }
             if (m_UseInverted)
             {
               m_EdgesPerThread[threadId][EdgePairType(vIt2.GetIndex(),vIt1.GetIndex())]=invert[value];