山东省菏泽市水氟空间分布特征的反距离加权插值法分析

Characteristics of spatial distribution of water fluoride in Heze City, Shandong Province based on inverse distance weighted

目的探讨反距离加权插值法（IDW）在分析山东省菏泽市水氟空间分布中的应用价值，探讨其空间分布特征。方法以2005—2007年间山东省地方病防治研究所的山东省菏泽市水氟监测资料为基础．应用地理信息系统（GIS）构建居民饮用水氟的乡级空间信息数据库。采用IDW对山东省菏泽市8个县2个区及139个乡镇水氟进行预测，并与实际测量值进行比较，计算灵敏度和特异度。结果菏泽市8个县2个区的水氟均值均〉1．0mg／L，其中曹县、巨野、牡丹区和鄄城的水氟值〉2．0mg／L。菏泽市所有139个乡镇中，其中高氟（〉1．0mg／L）129个，低氟（≤1．0mg／L）10个。IDW法分析显示，菏泽市绝大部分地区水氟含量在1．0-2．0mg／L。水氟含量〉2．0—3．0mg／L的区域主要分布于鄄城县的中东部、牡丹区的北部、成武县的中北部、巨野县的中南部、曹县的东南部和单县的东部；水氟〉3．0mg／L的区域主要分布在巨野县的谢集镇和万丰镇，鄄城县的吉山镇，曹县的孙老家镇和牡丹区的都司镇。内验证结果显示，应用IDW预测水氟含量的灵敏度为100．00％（129／129），特异度仅为10．00％（1／10），总体准确率为93．53％（130／139）。外验证结果显示．应用IDW预测水氟含量灵敏度、特异度分别为100．00％（31／31）、11．11％（1／9），总体准确率为80．00％（32／40）。结论利用IDW能够较好地通过监测点的数据推断总体的空间分布状况，确定山东省菏泽市水氟的空间分布特征。

Objective To evaluate the inverse distance weighted（IDW） in revealing the characteristics of spatial distribution of water fluoride in Heze City, Shandong Province. Methods A geographic information system （GIS） database of water fuoride was established in Heze City of Shandong Province using the data of endemic fluorosis surveys collected by Endemic Disease Prevention Institute in Shandong Province during 2005 - 2007. IDW spatial interpolation was applied to predict the distribution of fluoride in drinking water in 139 towns of Heze City. Sensitivity and specificity were calculated. Results Mean water fluoride levels in 10 counties of Heze City were all higher than 1.0 mg/L, and the water fluoride in Cao County, Juye, Mudan District and Juancheng were higher than 2.0 mg/L. Of all 139 townships of Heze City, 129 were higher fluoride townships where fluoride was 〉 1.0 mg/L, 10 were lower fluoride townships（ ≤ 1.0 mg/L）. IDW spatial interpolation showed that the water fluoride of most areas in Heze City were 〉 1.0 - 2.0 mg/L. The areas with water fluoride of 〉 2.0 - 3.0 mg/L were mainly located in eastern Juancheng, northern Mudan District, north-central Chengwu, central and southern Juye, southeastern part of Caoxian and eastern part of Shah Town. Regions of water fluoride 〉 3.0 mg/L were mainly distributed in Xieji and Wanfeng towns of Juye County, Jishan town of Juancheng County, Sunlaojia town of Caoxian and Dusi town of Mudan County. The internal verification results showed that the sensitivity, specificity and overall accuracy rate of IDW used for predicting water fluoride content was 100.00% （129/129）, 10.00% （1/10） and 93.53% （130/139）, respectively. While the external verification results showed that the sensitivity, specificity and overall accuracy rate of IDW for predicting water fluoride content was 100.00% （31/31 ）, 11.11% （1/9） and 80.00% （ 32/40）, respectively. Conclusion With the application of IDW interpolation,it is feasible to infer the overall spatial distribution based on the monitoring data, and to reveal the spatial characteristics of water fluoride in Heze City, Shandong Province.