diff --git a/Applications/FileIO/Gmsh/GMSHPolygonTree.cpp b/Applications/FileIO/Gmsh/GMSHPolygonTree.cpp
index 765c8c63484a672aeb7111b4046ab2b803f3d2d2..ac052d20c2a7ad6af0aa259697772c448d0065ef 100644
--- a/Applications/FileIO/Gmsh/GMSHPolygonTree.cpp
+++ b/Applications/FileIO/Gmsh/GMSHPolygonTree.cpp
@@ -501,7 +501,7 @@ void GMSHPolygonTree::writeAdditionalPointData(std::size_t& pnt_id_offset,
 }
 
 void GMSHPolygonTree::getPointsFromSubPolygons(
-    std::vector<GeoLib::Point const*>& pnts)
+    std::vector<GeoLib::Point const*>& pnts) const
 {
     for (std::list<SimplePolygonTree*>::const_iterator it(_children.begin());
          it != _children.end(); ++it)
@@ -511,7 +511,7 @@ void GMSHPolygonTree::getPointsFromSubPolygons(
 }
 
 void GMSHPolygonTree::getStationsInsideSubPolygons(
-    std::vector<GeoLib::Point const*>& stations)
+    std::vector<GeoLib::Point const*>& stations) const
 {
     const std::size_t n_stations(_stations.size());
     for (std::size_t k(0); k < n_stations; k++)
diff --git a/Applications/FileIO/Gmsh/GMSHPolygonTree.h b/Applications/FileIO/Gmsh/GMSHPolygonTree.h
index bcd17132b2267b62f4adc216d137f7dca40e3115..3f16aff8c305f4e169d1d5be7931481c8052c9a1 100644
--- a/Applications/FileIO/Gmsh/GMSHPolygonTree.h
+++ b/Applications/FileIO/Gmsh/GMSHPolygonTree.h
@@ -88,8 +88,10 @@ public:
     void writeAdditionalPointData(std::size_t & pnt_id_offset, std::size_t sfc_number, std::ostream& out) const;
 
 private:
-    void getPointsFromSubPolygons(std::vector<GeoLib::Point const*>& pnts);
-    void getStationsInsideSubPolygons(std::vector<GeoLib::Point const*>& stations);
+    void getPointsFromSubPolygons(
+        std::vector<GeoLib::Point const*>& pnts) const;
+    void getStationsInsideSubPolygons(
+        std::vector<GeoLib::Point const*>& stations) const;
     void checkIntersectionsSegmentExistingPolylines(
         GeoLib::PolylineWithSegmentMarker* ply,
         GeoLib::Polyline::SegmentIterator const& seg_it);