Enclosure structures of equal level line fields in the gradient filling problem

In this paper, the method of gradient filling of equal level line fields by color scale is considered. On the basis of this method, the linear structure and the root tree of equal level line enclosure are determined. The enclosure linear structure represents the sorted sequence of equal level lines in which the serial number of each enclosed equal level line becomes greater than the serial number of any other equal level line covering it. The root tree structure of equal level line enclosure is applied to the context analysis of all equal level line values in order to correctly specify the color values of their filling. A working algorithm of gradient filling of equal level lines is given.