diff --git a/topography_generator/generator.cpp b/topography_generator/generator.cpp
index 6a997aa627..e84550c221 100644
--- a/topography_generator/generator.cpp
+++ b/topography_generator/generator.cpp
@@ -101,6 +101,7 @@ private:
   {
     auto const tileName = generator::SrtmTile::GetBase(ms::LatLon(lat, lon));
     LOG(LINFO, ("Begin generating isolines for tile", tileName));
+
     ms::LatLon const leftBottom = ms::LatLon(lat, lon);
     ms::LatLon const rightTop = ms::LatLon(lat + 1.0, lon + 1.0);
     double const squaresStep = 1.0 / (kArcSecondsInDegree) * m_params.m_latLonStepFactor;
@@ -126,7 +127,11 @@ private:
       squares.GenerateContours(contours);
     }
 
+    LOG(LINFO, ("Isolines for tile", tileName, "min altitude", contours.m_minValue,
+      "max altitude", contours.m_maxValue, "invalid values count", contours.m_invalidValuesCount));
+
     SaveContrours(GetIsolinesFilePath(lat, lon, m_params.m_outputDir), std::move(contours));
+
     LOG(LINFO, ("End generating isolines for tile", tileName));
   }
 
diff --git a/topography_generator/marching_squares/contours_builder.cpp b/topography_generator/marching_squares/contours_builder.cpp
index 4c5156894e..d399f70c86 100644
--- a/topography_generator/marching_squares/contours_builder.cpp
+++ b/topography_generator/marching_squares/contours_builder.cpp
@@ -40,7 +40,7 @@ void ContoursBuilder::AddSegment(size_t levelInd, ms::LatLon const & beginPos, m
   else if (connectEnd)
   {
     contourItAfter->m_countour.push_front(beginPos);
-    contourItBefore->m_active = true;
+    contourItAfter->m_active = true;
   }
   else
   {
diff --git a/topography_generator/marching_squares/marching_squares.hpp b/topography_generator/marching_squares/marching_squares.hpp
index a57bd55856..fb204235da 100644
--- a/topography_generator/marching_squares/marching_squares.hpp
+++ b/topography_generator/marching_squares/marching_squares.hpp
@@ -44,16 +44,16 @@ public:
 
     ContoursBuilder contoursBuilder(levelsCount);
 
-    for (size_t i = 0; i < m_stepsCountLat - 1; ++i)
+    for (size_t i = 0; i < m_stepsCountLat; ++i)
     {
       contoursBuilder.BeginLine();
-      for (size_t j = 0; j < m_stepsCountLon - 1; ++j)
+      for (size_t j = 0; j < m_stepsCountLon; ++j)
       {
         auto const pos = ms::LatLon(m_leftBottom.m_lat + m_step * i, m_leftBottom.m_lon + m_step * j);
         Square<ValueType> square(pos, m_step, result.m_minValue, m_valueStep, m_valuesProvider);
         square.GenerateSegments(contoursBuilder);
       }
-      auto const isLastLine = i == m_stepsCountLat - 2;
+      auto const isLastLine = i == m_stepsCountLat - 1;
       contoursBuilder.EndLine(isLastLine);
     }
 
@@ -66,9 +66,9 @@ private:
     minValue = maxValue = m_valuesProvider.GetValue(m_leftBottom);
     invalidValuesCount = 0;
 
-    for (size_t i = 0; i < m_stepsCountLat; ++i)
+    for (size_t i = 0; i <= m_stepsCountLat; ++i)
     {
-      for (size_t j = 0; j < m_stepsCountLon; ++j)
+      for (size_t j = 0; j <= m_stepsCountLon; ++j)
       {
         auto const pos = ms::LatLon(m_leftBottom.m_lat + m_step * i,
                                     m_leftBottom.m_lon + m_step * j);
diff --git a/topography_generator/utils/contours_serdes.hpp b/topography_generator/utils/contours_serdes.hpp
index a03948b9e1..34d6993e9f 100644
--- a/topography_generator/utils/contours_serdes.hpp
+++ b/topography_generator/utils/contours_serdes.hpp
@@ -20,6 +20,7 @@ public:
     WriteToSink(sink, m_contours.m_minValue);
     WriteToSink(sink, m_contours.m_maxValue);
     WriteToSink(sink, m_contours.m_valueStep);
+    WriteToSink(sink, static_cast<uint32_t>(m_contours.m_invalidValuesCount));
 
     WriteToSink(sink, static_cast<uint32_t>(m_contours.m_contours.size()));
     for (auto const & levelContours : m_contours.m_contours)
@@ -35,23 +36,17 @@ private:
     WriteToSink(sink, value);
     WriteToSink(sink, static_cast<uint32_t>(contours.size()));
     for (auto const & contour : contours)
-    {
       SerializeContour(sink, contour);
-    }
   }
 
   template <typename Sink>
   void SerializeContour(Sink & sink, topography_generator::Contour const & contour)
   {
-    WriteToSink(sink, static_cast<uint32_t>(contour.size()));
-    sink.Write(contour.data(), contour.size() * sizeof(contour[0]));
-    /*
-    serial::GeometryCodingParams codingParams(kFeatureSorterPointCoordBits, 0);
+    serial::GeometryCodingParams codingParams;
+    serial::SavePoint(sink, contour[0], codingParams);
     codingParams.SetBasePoint(contour[0]);
-    std::vector<m2::PointD> toSave;
-    toSave.insert(contour.begin() + 1, contour.end());
-    serial::SaveInnerPath(toSave, codingParams, sink);
-    */
+    std::vector<m2::PointD> toSave(contour.begin() + 1, contour.end());
+    serial::SaveOuterPath(contour, codingParams, sink);
   }
 
   Contours<ValueType> m_contours;
@@ -68,6 +63,7 @@ public:
     contours.m_minValue = ReadPrimitiveFromSource<ValueType>(source);
     contours.m_maxValue = ReadPrimitiveFromSource<ValueType>(source);
     contours.m_valueStep = ReadPrimitiveFromSource<ValueType>(source);
+    contours.m_invalidValuesCount = ReadPrimitiveFromSource<uint32_t>(source);
 
     size_t const levelsCount = ReadPrimitiveFromSource<uint32_t>(source);
     for (size_t i = 0; i < levelsCount; ++i)
@@ -93,9 +89,12 @@ private:
   void DeserializeContour(NonOwningReaderSource & source,
                           topography_generator::Contour & contour)
   {
-    size_t const pointsCount = ReadPrimitiveFromSource<uint32_t>(source);
-    contour.resize(pointsCount);
-    source.Read(contour.data(), pointsCount * sizeof(contour[0]));
+    serial::GeometryCodingParams codingParams;
+    auto const pt = serial::LoadPoint(source, codingParams);
+    codingParams.SetBasePoint(pt);
+    std::vector<m2::PointD> points;
+    serial::LoadOuterPath(source, codingParams, points);
+    contour.swap(points);
   }
 };