Indeed, as was specified by @Gabriel De Luca, I required some interpolation as well as contour lines.
After I produced nodes from isolines, I have applied a QGIS-Contour-Plugin which worked much better than any previous solution.
Indeed, as was specified by @Gabriel De Luca, I required some interpolation as well as contour lines.
After I produced nodes from isolines, I have applied a QGIS-Contour-Plugin which worked much better than any previous solution.