GIS-based analysis of spatial interpolations of sediments grain size in Heini Bay

Interpolation applications on grain size parameters distribution of surface sediments in Heini Bay with GIS-based methods were discussed.Four interpolation methods(IDW,Kriging,Spline,NN) were compared and the factors influencing the interpolation accuracy were discussed from several aspects.The results indicate that considering interpolation accuracy and spatial expression IDW is relatively best among four interpolation methods in process of grain size parameter interpolation in Heini Bay.But "bulls eye" effects should be considered in IDW.Kriging and NN methods have a high accuracy and relatively bad spatial description.The applications of Spline methods isn't adaptive to grain size interpolation in nearshore sea.Compared with dissimilarity of different interpolation methods inner regularity,spatial distributions and sampling density contribute more in interpolation precision.The grain sizes have a thinning tendency seaward on control of steady currents and topography elements.The study also showed that interpolation errors are typically smaller in proportional spacing regions than that in border and abrupt-changing regions.The interpolation errors of different methods are all positive correlative to the sampling density in-situ.