中文摘要：

对于大面积的大比例尺珊瑚礁遥感制图而言,SPOT5数据是一种高性价比卫星遥感资料.以Quickbird2数据对东沙环礁珊瑚礁的分类、解译的矢量结果作为该区域实际的珊瑚礁分布,以此为基础分析SPOT5数据的珊瑚礁遥感制图能力.SPOT5只有两个水体穿透信道,从基于光谱数据的分类角度看,以XS1通道为准的珊瑚礁信息提取易将高反射的沙底质归为珊瑚礁;以XS2通道为准的珊瑚礁分布制图存在提取不足问题.由于空间分辨率提高,对潟湖淤泥质中的珊瑚礁提取能力较强,要优于ETM数据.结合ETM数据及PCA融合后的SPOT5的遥感解译结果,能提高SPOT5数据的制图能力.

英文摘要：

Coral reefs are an environment-sensitive complex marine ecosystem. The ecosystem of corals is rich in biodiversity. Remote sensing offers a powerful tool for categorizing coral reefs and is the most effective approach for large-scale reef surveys. The Dongsha Atoll is located on the northern continental margin of the South China Sea. The area of the atoll is more than 300 km^2 with an average depth of 10 m, and has being abused by destructive fishing during recent decades, the capabilities of SPOT5 imagery are evaluated to provide data that are useful for categorizing the current distribution of corals in the Dongsha Atoll. Three satellite imageries （Quickbird2, ETM＋, and SPOT5） are used to survey this area. In data processing, unsupervised classification functions are adopted for ETM＋ and SPOT5 data, and a supervised classi- fication method is used for Quickbird2. The classes are （or not） merged into coral reef, and then will be operated by vectorization, simplification, and topological analysis. There are 1 331 coral reefs larger than 100 m^2 with the detection limitation of 3 × 3 pixels at multi-band data of Quickbird2. This is taken as the comparison-baseline. The results extracted from SPOT5 and ETM images are less in number and area than from Quickbird2 image. And the results from SPOT5 data are better than those of ETM data at silty lagoon due to its higher resolution. SPOT XS Band 2 is failed to show the deep substrate inside the atoll comparing with ETM data because of its penetration capability. Only SPOT XS Band 1 cannot differentiate coral reef from sand bottom. Merging the spectral qualities of SPOT5 multi-bands data with the spatial resolution of SPOT5 Pan data and referring to ETM imagery are expected to provide an optimum satellitebased approach to habitat mapping.