将数字化好的秦安县土壤图、土地利用现状图、行政区划图叠加求交生成耕地资源评价单元,并分别对评价单元数据层中实体面积小于7000、15000m2的小多边形进行合并及不合并多边形,从而对三种不同的小多边形合并方法产生的评价单元分别进行耕地地力评价结果比较.结果表明:以实体面积小于15000m2合并多边形得到的评价单元,由于评价单元面积较大,致使地貌类型作为评价因子的贡献率较小,从而影响评价结果,导致评价结果与实际情况存在较大差异；不合并多边形得到的评价单元,由于评价单元过小,定点测到的数据空间插值后不能具体到很小面积的区域上,从而影响评价结果.结论:地貌类型作为重要的参评因子及研究区域地域面积大小共同决定评价单元面积的大小.%This paper established an evaluation index system with nine indicators, such as water quantity per capita, water resources development and utilization level, COD concentration, per capita grain possession, water consumption per capita, natural growth rate of population, per capita GDP, water-use efficiency and environmental water use rate. A comprehensive evaluation of water resources carrying capacity in Yulin was carried out by principal component analysis, through which four principal components were given. The results show that: water resources carrying capacity is in unbalanced distribution in Yulin and the comprehensive evaluation value is different. The comprehensive evaluation values of Hengshan, Dingbian, Fugu, Yuyung and Shenmu are between 1 365.12 and 10 447.86, which are in the middle level. Water resources carrying capacity is limited in Jingbian and its comprehensive evaluation value is 10 468. 962 ( > 10 447.86) , which is slightly larger than Grade I standard. In other divisions, such as Zizhou, Jiaxian, Qingjian, Suide, Mizhi and Wubu, they have a great exploitation potentiality and their evaluating values are lower than 1 365.12, the Grade 31 standard. At last countermeasures are proposed to improve the water resources carrying capacity, which have important practical significance for optimizing water resources allocation and promoting sustainable development of the social economy in Yulin.
展开▼
