分层分区分景相结合的区域土地利用/覆盖分类方法——以浙江钱塘江流域分类为例

在土地利用/覆盖研究中，对于范围广、地域差别大的地区，仅用同一标准对遥感图像进行分类往往难以得到理想的效果。 本文以浙江省钱塘江流域为例，通过对Landsat TM数据各波段组合，首先提取水层和山层信息，然后采用掩模法提取平原丘陵层信 息，并根据地形地貌和土地利用现状的差异，将平原丘陵层划分为6个区，当所划分区域内各景的影像时相不一致时，再对该区进 行分景处理。最后，分别对每层、每区和每景图像进行训练样本的选择和监督分类。试验结果表明，结合分层、分区和分景的监督 分类方法是一种适合于较大区域土地利用/土地覆盖分类的有效方法。

REGIONAL LAND USE/COVER CLASSIFICATION WITH A STRATIFIED AND REGIONALIZED APPROACH: A CASE STUDY IN QIANTANG RIVER WATERSHED, ZHEJIANG PROVINCE

In land use/land cover classification,the utilization of large-scale routine approaches in diverse areas often fails to obtain satisfactory results.In this paper,the Qiantang river watershed was chosen as the study area.A stratified and regionalized supervised classification(the Maximum Likelihood Classification) approach was employed.With this approach,water and mountain areas were first stratified and extracted through a set of equations that were used to compute parameters from Landsat TM bands.Subsequently,by using the mask method,the authors obtained plains and foothills,which were subdivided into six sub-regions according to the geomorphic features and land use/cover characteristics.Additionally,the plains and foothills should be classified separately in the case the images were acquired in different seasons.The supervised classification could be carried out after respective signatures in every region were identified.The classification accuracy reached 90.7% with a Kappa coefficient of 0.881,which was much higher than that obtained from the routine classification approach that had a classification accuracy of 51.6% and a Kappa coefficient of 0.411.This study shows that the stratified and regionalized approach is very efficient in land use/cover classification in a fairly large region,such as the watershed level in southern China.