Using remote sensing and geographical information technology, 5 remote sensing images were analyzed, the land using change of the Yongding River ( Beijing section) from 1987 to 2009 had showed that: ① the Yongding River water was gradually declining, but with the government' attention to these issues and appropriate measures taken, the annual declining rate of Yongding River water eased. ② With the social and economic development, Beijing city will expand to the Yongding River basin so that residential areas were in rapid growth followed by an annual growth rate at 1. 41% , 2. 78% , 3. 96% and 5. 06% , arable land area was decreasing annually. ③land transfer and land use change mapping matrix inl987 and 2009 showed that, the residential land increase were mainly from changes in arable land, and water area transferred to arable land. ④woodland changes in the Yongding River basin were mixed, in the past 23 years, the government has implemented policies such as returning farmland to forests, resulted in forest area back to 8198. 62 km in 2009, the Yongding River ecological environment has improved significantly.%利用遥感技术和地理信息技术对5期遥感影像进行处理分析,得出永定河流域(北京段)1987 ～2009年土地利用变化情况,即:①永定河流域水量在逐年递减,但随着政府部门对这些问题的重视并采取了相应的措施,使永定河流域的水量年递减速度有所缓解.②随着社会经济的发展,北京城区将向永定河流域扩张,从而使永定河流域居民用地迅速增长,年增长率依次为1.41％、2.78％、3.96％和5.06％,耕地面积在逐年减少.③从1987年和2009年土地转移矩阵和土地利用变化图谱中可以看出,居民地的增加主要来自于耕地的转变,而水域面积转移到了耕地上.④永定河流域林地面积有升有降,在这23年间,政府推行退耕还林等政策,2009年林地面积恢复到8 198.62km2,使永定河流域的生态环境有了明显改善.
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