diff --git a/PolyLine.cpp b/PolyLine.cpp
index 97fe40a..b89aae7 100644
--- a/PolyLine.cpp
+++ b/PolyLine.cpp
@@ -783,11 +783,11 @@ PolyLine::RemoveAlignedPoints( double dToler)
    dToler = max( dToler, LIN_TOL_MIN) ;
    double dSqTol = dToler * dToler ;
   // vettore contenente i punti della polyline
-   PNTUVECTOR vPtU ; vPtU.reserve( int( m_lUPoints.size())) ;
+   PNTUVECTOR vPtU ; vPtU.resize( int( m_lUPoints.size())) ;
   // interatore primo punto
    auto ptAct = m_lUPoints.begin() ;
    for ( int i = 0 ; i < int( m_lUPoints.size()) ; ++ i) {
-      vPtU[i] = *ptAct ;
+      vPtU[i] = *ptAct;
       ptAct = next( ptAct) ; // incremento iteratore
    }
 
@@ -797,25 +797,41 @@ PolyLine::RemoveAlignedPoints( double dToler)
   // POLYLINE APERTA
    if ( ! IsClosed()) {
      // considero tutti i punti della PolyLine
+      vPtU_simple.push_back( vPtU.front()) ;
       if ( ! douglasPeuckerSimplification( vPtU, dSqTol, 0, int( vPtU.size()) - 1, vPtU_simple))
          return false ;
+      vPtU_simple.push_back( vPtU.back()) ;
    }
   // POLYLINE CHIUSA
    else {
-     // considero tutti i punti della PolyLine ad eccezione degli ultimi due
-      if ( ! douglasPeuckerSimplification( vPtU, dSqTol, 0, int( vPtU.size()) - 2, vPtU_simple))
+     // cerco il punto pił distante dal primo
+      double dMaxDist = 0. ;
+      int nMaxInd = 0 ;
+      for ( int i = 1 ; i < int( vPtU.size()) ; ++ i) {
+         double dCurrDist = Dist( vPtU[0].first, vPtU[i].first) ;
+         if ( dCurrDist > dMaxDist) {
+            dMaxDist = dCurrDist ;
+            nMaxInd = i ;
+         }
+      }
+     // recupero due PolyLine di approssimazione
+      vPtU_simple.push_back( vPtU.front()) ;
+      if ( ! douglasPeuckerSimplification( vPtU, dSqTol, 0, nMaxInd, vPtU_simple))
          return false ;
-     // controllo se includere l'ultimo punto, calcolando la distanza tra esso e la retta
-     // definita dagli estremi dei punti semplificati ( primo ed ultimo)
-      double dLastSqDist = 0. ;
-      DistPointLine DPL( vPtU.back().first, vPtU_simple.front().first, vPtU_simple.back().first) ;
-      if ( DPL.GetSqDist( dLastSqDist)  &&  dLastSqDist > dSqTol)
-         vPtU_simple.push_back( vPtU.back()) ;
+      vPtU_simple.push_back( vPtU[ nMaxInd]) ;
+      if ( ! douglasPeuckerSimplification( vPtU, dSqTol, nMaxInd, int( vPtU.size()) - 1, vPtU_simple))
+         return false ;
+      vPtU_simple.push_back( vPtU.back()) ;
    }
 
+  // ordino
+   sort( vPtU_simple.begin(), vPtU_simple.end(),
+         []( const POINTU& a , const POINTU& b) { return ( a.second < b.second) ; }) ;
+
   // pulisco e aggiungo i parametri ricavati
    m_lUPoints.clear() ;
-   copy( vPtU_simple.begin(), vPtU_simple.end(), m_lUPoints.begin()) ;
+   for ( int i = 0 ; i < int( vPtU_simple.size()) ; ++ i)
+      m_lUPoints.push_back( vPtU_simple[i]) ;
 
    return true ;
 }