Ecosystem is made up aquatic and terrestrial components, in turn form biosphere. Aquatic ecosystem covers up to seventy percent of earth surface. Marine ecosystem accounts for the highest valuable biodiversity with diverse and sustainable habitats among others. Coral islands are found to be one of the most important aquatic ecosystem compared to others because of unique characteristic, rareness, high diversity and advantages that they provide for costal residents. Nowadays, they are subjected to different destructive factors and it is expected that about 11 percent of these productive and diverse habitats are about to degradation. Exact spatial data serve as a prerequisite to make better decision for coastal areas. Remote sensing is one of the appropriate tools to study and recognize coral reefs habitats. Although advanced satellite images have been developed in early 1980s for marine investigations, however, there are some limitations on features justify; MARGIN: 0cm 0cm 0pt" Keywords : satellite images, coral reefs, pre-processing, justify; MARGIN: 0cm 0cm 0pt"
