Shallow-Water Bathymetry Over Variable Bottom Types Using Multispectral Worldview-2 Image

Abstract

ABSTRACT:Image processing techniques that involve multispectral remotely sensed data are considered attractive for bathymetry applications as they provide a time-and cost-effective solution to water depths estimation. In this paper the potential of 8-bands image acquired by Worldview-2 satellite in providing precise depth measurements was investigated. Multispectral image information was integrated with available echo sounding and GPS data for the determination of the depth in the area of interest. In particular the main objective of this research was to evaluate the effectiveness of high spatial and spectral resolution of the new imagery data on water depth measurements using the Lyzenga linear bathymetry model. The existence of sea grass in a part of the study area influenced the linear relationship between water reflectance and depth. Therefore the bathymetric model was applied in three image parts: an area with sea grass, a mixed area and a sea grass-free area. In the last two areas the model worked successfully supported by the multiplicity of the imagery bands.

Bathymetry Determination from High Resolution Satellite Imagery Using Ensemble Learning Algorithms in Shallow Lakes: Case Study El-Burullus Lake

“…Some of these LIDAR systems can reach 70 m depths and 20 cm vertical accuracy [11]. Despite of the accuracy of these systems they are limited in coverage compared to satellite images and high costing of operation [12].Remote Sensing Multi-spectral satellite images are considered the feasible alternative method for bathymetric estimation [9]. These images precede the LIDAR methods in their wide coverage, low costs, high spatial resolution and suitability for shallow areas.…”

“…Although these methods gives high accuracy with about 8 cm in 200 m water depths and high spatial resolution of 6 m, they have many limitations. These methods are time consuming, expensive, have low coverage areas and not appropriate for some places as shallow areas with depths less than 3 m [9].Airborne LIDAR measurements represent another method for accurate water depths detection especially in the last years. LIDAR systems are fast, accurate and appropriate alternative solution for difficult shallow aquatic areas [10].…”

“…Although these methods gives high accuracy with about 8 cm in 200 m water depths and high spatial resolution of 6 m, they have many limitations. These methods are time consuming, expensive, have low coverage areas and not appropriate for some places as shallow areas with depths less than 3 m [9].…”

“…Remote Sensing Multi-spectral satellite images are considered the feasible alternative method for bathymetric estimation [9]. These images precede the LIDAR methods in their wide coverage, low costs, high spatial resolution and suitability for shallow areas.…”

“…According to many researchers the preferred method for bathymetry detection is dark pixel subtraction method [17]. The corrected pixel value can be calculated as follows [9]:where: R ac = corrected pixel reflectance value R i = initial pixel reflectance value R dp = the dark pixel value. The dark pixel value is so important for depths determination process and influence the accuracy of depth estimation values [16].…”