By using local data points Triangulated Irregular Network(TIN) was generated,the skeleton method was used to remove triangle points with same elevation,then the multi local quadrics were generated,al last the quadrics were used to conduct weighted interpolation in their vicinities so that the quadrics can be smoothed and an accurate and smooth surface was obtained.

In Hongfenghu long Span Bridge construction,stiff skeleton method is adopted to implement closure of main span and side span, by taking a series of measures to assure construction quality,the safe of structure stress and the easement of main beam alignment are assured in the course of closure segment construction.