Identification and Analysis Coral Reefs Changes Using Landsat 8 OLI Imagery in Coastal Zone of Langsa City

Abstract

This study aims to examine the accuracy of Landsat 8 OLI imagery in mapping spatial distribution, analyzing changes in the area, and factors that affect coral reefs changes in the coastal areas of Langsa City in 2014, 2016, and 2018. The classification methods used in this study are the multispectral classification of parallelepiped algorithms and field surveys using the photo transect method. The results of this study are (1) the level of accuracy of Landsat 8 OLI imagery for the mapping of coral reefs on the coast of Langsa City is 42.50%; (2) the coral reef in the coast of Langsa City has increased 1,372.77 Ha in 2014-2016 and decrease1,386 Ha in 2016-2018 the dominant factor affecting these changes was the water temperatures above the average of 34.14°C, while dissolved oxygen levels, water pH, and salinity is at a limit that can still be tolerated by coral reefs.