Shallow water depth determination by using remote sensing at Lang Tengah Island, Terengganu

Abstract

The traditional hydrographical surveys are conducted via shipboard echo sounding. This traditional method is able to generate accurate water depth but it is high operating cost, labor-intensive, time-consuming and inefficiency. To overcome this problem, the application of remote sensing in bathymetry study has been extensively explored in recent years. Compared to the traditional method, satellite remote sensing technique is more cost-effective, easier and quicker. Besides, bathymetric measurement via remote sensing also has the advantage that the data are collected synoptically over large areas. This study is discusses the determination ofbathymetry of a shallow water area applying remote sensing techniques at Lang Tengah Island, Terengganu. There are two methods used in this study, which is linear method (Benny and Dawson method) and ratio method. Both methods require the same preprocessing process, included geometric correction, atmospheric correction, and masking. The results obtained were compared with ground truth data. The accuracy of the methods is discussed and the compared between the two methods. The result shows that Band 2 for Benny and Dawson method has the highest correlation coefficient, R2 , among the three bands, which is 0.9533. Ratio method has a higher R2 compared to the Band 2 for Benny and Dawson method as its R2 achieve 0.9607. Ratio method is better in deriving bathymetry from satellite imagery compared to linear method. Ratio method is more robust as it only needs two tunable parameters whereas linear method requires more than two tunable parameters.