基于RS、GIS的岷县草场退化的时空特征研究

Spatio-temporal feature of grassland degradation in MinXian based on RS & GIS method

本文运用遥感手段,对2000年6月份的TM影像解译得到岷县草场资源分布图,对比分析1981年的岷县草场资源分布,对岷县草场退化的时空特征进行研究。经过IMoran'的全局空间自相关计算、局域空间自相关计算—G*统计的)(*iGZ值的计算,发现岷县的草场退化重心位于县域的西北部;20年来草场资源一直呈现东多西少、南好北差之势,并且这种空间格局愈加明显。表现为县域的西北部和中部的草场呈现大面积的集中退化的趋势,而东部的几个乡镇的草场面积还有增加的现象。说明县域的西北部和中部的科技水平以及草场保护投入的资金相对不足,抗干扰能力差。

Based on the data of grassland investigation in 1981 and grassland distribution calculated from TM remote sensing image by means of GIS technology in 2000, the spatial and temporal dynamic of in MinXians grassland is monitored. Contrasting the grassland of 1981 with one of 2000, the spatial feature of degradation would be researched in the paper. To most spatial analysts, IMoran' is probably a known measure to test spatial autocorrelation, and the Z-value of IMoran' indicates positive spatial autocorrelation. The results of IMoran' and Z(Gi*) and the moving plots all shows that the center of grassland degradation is the XiJiang village which is at the northwest of MinXian. From 1981 to 2000, the quantities of grasslands in the east are more than in the west, and the qualities of grasslands in the south are better than in the north. And the spatial structure of grassland is more obviously than before in the MinXian. It shows that the grassland is centralized degenerated in the northwest and middle of the MinXian, but the grassland of the some villages would be increasing in the east. It is caused by the lagging of the economic and technology. In other words, little money and poor technology are used in the area. So the area is weak to the disturbance from the environments.