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以“5·12”地震前后的TM影像为数据源,根据研究区特殊的地貌特征和灾毁分布特征,采用分区处理的方法,提取了地震前后彭州市土地利用图。彭州市灾毁面积达200.53km2,占彭州市总面积的14%。提出以R(4)G(2)B(7)波段组合的影像图来区分河流与灾毁,可以大大提高灾毁提取的精度与速度。将灾毁信息与高程数据、坡度数据、坡向数据进行叠加分析,得出:灾毁与高程成正相关;随着坡度的增加,灾毁比例先增后减,灾毁最严重的坡度为35°～55°;西—西南向灾毁比例相对较高,东—东南向灾毁比例较低。
According to the special geomorphic features and disaster distribution features of the study area, the TM images before and after the “May 12” earthquake were used as data sources and the land use maps of Pengzhou City before and after the earthquake were extracted by the method of zoning treatment. Pengzhou disaster area reached 200.53km2, accounting for 14% of the total area of Pengzhou. In this paper, the image of R (4) G (2) B (7) band combination is proposed to distinguish rivers from disaster, which can greatly improve the accuracy and speed of disaster recovery. According to the superimposed analysis of disaster information with elevation data, slope data and aspect data, it is concluded that there is a positive correlation between disaster and elevation. With the increase of slope, the proportion of disaster increases first and then decrease, and the most serious slope is 35 ° ~ 55 °; the ratio of west-southwest disaster is relatively high, and the ratio of east-southeast disaster is low.