云南省元阳梯田遥感辅助识别特征研究

深入分析和研究元阳梯田的空间分布规律及其光谱特征，能够为今后元阳梯田的遥感分类识别提供专家知识，克服传统地面调查方法的弊端，及时准确地掌握元阳梯田的空间分布及动态变化情况，为有效保护、合理利用元阳梯田提供基础依据。在对元阳梯田进行基于SPOT5的目视解译分类的基础上，提取了各梯田斑块中心点上的海拔、坡度、坡向、MODIS-NDVI以及Landsat TM各波段上的像元亮度值，分别从元阳梯田的空间分布特征、植被指数特征和像元亮度特征三个方面，提取和归纳了元阳梯田的遥感辅助识别特征。结果表明，影响元阳梯田空间分布的环境因子按影响程度由大到小依次为海拔 > 坡度 > 坡向，主要分布于海拔1 000~1 400 m、坡度12°~33°、北坡和东北坡；随着梯田斑块面积的逐渐增大，MODIS-NDVI平均值则逐渐减小，总体平均值为0.754，最小值为0.378，最大值为0.849；元阳梯田在可见光波段（B10，B20，B30）的DN值较低，在近红外波段（B40）的DN值较高，各面积的等级元阳梯田在Landsat TM数据各波段上的像元亮度曲线趋近一致。

Assistant Classification Feature of Terrace in Yuanyang County of Yunnan Province Based on Remote Sensing

The analysis and study on the spatial distribution characteristics and spectral characteristics of terrace in Yuanyang County could provide expert knowledge for the classification and recognition based on remote sensing. The deficiency of traditional inventory method would be overcome, and the spatial distribution and the dynamic changes could be accurately monitored. Based on the visual interpretation of terrace in Yuanyang County using the data of SPOT5 image, the information on altitude, slope, aspect, MODIS-NDVI and DN of Landsat TM bands were extracted. The assistant classification feature of terrace including the aspects of spatial distribution characteristic, vegetation index characteristic, and pixel DN characteristic in Yuanyang County was studied. The results showed that: a) the sequence of the influence extent was altitude > slope > aspect, the terrace in Yuanyang County mainly distributed in the area with altitude of 1 000~1 400 m, slope of 12°~33° and aspect of north and northeast; b) the average of MODIS-NDVI decreased gradually with the increase of patch area, the population mean of MODIS-NDVI was 0.754, the minimum was 0.378 and the maximum was 0.849; c) the value of pixel DN was low in visible bands, and it would be high in near-infrared bands. The band curve of Landsat TM pixel DN on the different grades showed the same trend.