基于波谱角分类法的沙化信息提取研究--以毛乌素沙地典型地区为例

THE EXTRACTION OF DESERTIFICATION INFORMATION BASED ON SPECTRAL ANGLE MAPPER:A CASE STUDY OF THE MU US SANDY LAND

以毛乌素沙地典型地区为例,以CBERS-2、Landsat 5 TM、SPOT5及TM与SPOT5融合影像作为基本数据源,使用波谱角分类法对该区流动沙地、半固定沙地、固定沙地和沙化耕地进行信息提取,探索和比较该方法针对不同传感器遥感影像的沙化信息提取精度。对本研究区,不同传感器影像的沙化信息提取精度均在80%以上,其中融合影像的沙化信息提取精度最高为90.13%,SPOT5次之,而CBERS-2和TM对不同类型的沙化信息提取各有优势,但CBERS-2信息提取的精度要高于TM。这说明使用波谱角分类法提取的结果精度与影像空间分辨率有正相关关系,即空间分辨率越高,沙化信息的提取精度也越高。

In this study, the Spectral Angle Mapper method was used to extract such kinds of desertification information as flow sand, semi -fixed sand, fixed sand and sandy plantation, and the Mu Us sandy land was chosen as a typical study area. CBERS -2, Landsat 5 TM, SPOT 5, TM and SPOT 5 fusion images were obtained as the source of data to study and compare the extraction precision from different sensors. The results show that the extraction precisions from different sensors all reach 80%. The fusion image has the highest extraction precision, the SPOT 5 image possesses the second place, and the CBERS -2 and TM images have different advantages in extracting different sorts of desertification information, but the precision of CBERS - 2 is on the whole higher than that of TM. It is concluded that there exists a positive relationship between the extraction results and the space resolution of image, i. e. , the higher the space resolution, the higher the extraction precision.