T he fracta l p lot of the num ber of boxes N con ta in ing data is p lotted versus the box s ize r in lg-lgspace.T he slope of a stra igh t-line fitted through the data is fracta l d im ens ion D.

• 用边长为r的正方形格子覆盖研究区；当格子大小变化时；将含有矿床的格子数N与格子边长r投在双对数坐标图上；通过对数据点拟合得到的直线的斜率求得分维数D F ig.