Results: The variograms model and its epidemiology implication were obtained.
结果：获得疾病空间分布变异函数模型及其流行病学含义。
The variograms of arsenic persistently increased and could be fitted by exponential equation.
土壤砷含量半方差值呈有规律持续增加趋势，可用指数方程很好地拟合。
The fractal dimensions of soil cone indices were estimated in semi-variograms and power, spectral densities, which were all very close to 2.
运用分形和分维理论，用半方差法和功率谱密度法分别计算土壤强度的分维，其值接近2。
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