基于ArcGIS的金沙江流域中段植被指数分布规律研究

Distribution Patterns of Vegetation Index Based on ArcGIS in the Middle Sect of Jinsha River Watershed

植被指数是描述地表植被覆盖程度的重要参数。以金沙江流域中段为研究区域,选取NDVI为植被指数,以2006年的TM数据为遥感数据源,使用ERDAS软件从遥感影像中提取NDVI,并使用Ar-cGIS对NDVI进行空间分布特征的研究。然后,在此基础上,结合海拔、坡度、降水、温度等地学因子,分别与NDVI进行空间分布的相关性研究。研究结果表明,NDVI在研究区内从西向东、从北向南有递减的趋势,并且与海拔总体上具有正相关性,即随着海拔的增加NDVI有上升的趋势,而与坡度,温度和降水量总体上不具有相关性,但在局部范围内有一定的相关性。由于海拔、坡度是影响人类活动分布的主要因素,也即说明人类活动对植被的破坏,是影响区域内植被指数空间分布规律的主要原因。研究成果有利于管理部门掌握区域内的植被分布状况,及影响植被分布的原因,为增强流域内的植被保护提供科学依据。

Vegetation index is one of the important parameters to descript vegetation coverage.Using remote sense data LandSat-TM of 2006,this paper studied the vegetation index-NDVI and its spatial distribution patterns with ArcGIS software in the middle sect of Jinsha river watershed.Based on this research,the relationship between NDVI and geo-dynamics,such as elevation,slope grade,precipitation,and temperature,was studied too.The results of this study are as follows.NDVI decrease gradually from west to east,and north to south.NDVI has positive relationship with elevation,but has no relationship with slope grade,precipitation and temperature,except some small bands.Furthermore,as elevation and slope grade are main factors to affect human activity intensity in Jinsha river watershed,it can be pointed out that human activity is the main reason to influence the vegetation index distribution patterns.Additionally,the result of this research may supply reference for forest managers to master plant distribution and its causation;and offer science evidence for plant protection in the watershed.