In many case, the data set to be visualized is generally a discrete grid data, while data between the grid could be got by
using the interpolation method. Drawing module of the visualization system generally does not directly interpolated
data in the grid, but to use the functionality provided by the computer hardware directly to the RGB color value of the color interpolation calculation. The actual color table can be used to solve this problem, because the color table index is completely linear mapping between the data and the colors. Generally the index is the row number in color map. If we have data set D = {D1,D2 ,...,Dn} , the color mapping is as formula (6).