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Data Series 1070


Single-Beam Bathymetry Data Collected in 2015 From Grand Bay, Alabama-Mississippi

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Citation Page
Abstract
Introduction
Survey Overview
Data Acquisition
Data Processing
Error Analysis
Survey Products
Abbreviations
Selected References
 

Error Analysis

Digital Elevation Model Error

To evaluate how well the DEM represented the final sounding data, a comparison of the DEM cell values versus the final point elevations was plotted in ArcGIS using a tool that extracts grid values and compares them with those of the overlying point data. The RMS error, representing the difference between the measured depth and the interpolated depth values, was calculated for each platform using the following equation:

equation

There is a total of 3,699,100 point elevations represented by the 30-m grid, and the root mean square error of all points is 0.07 m. The 10-m grid accounts for 3,782,849 point elevations and has an RMS of 0.04. To represent the spatial distribution of grid error, the difference between the DEM and the original sounding values were plotted, color coded, and overlaid on each DEM (figs. 8, 9).

Error values representing the difference between the 10-m digital elevation model and the value at each sample point.
Figure 8. Error values representing the difference between the 10-m digital elevation model and the value at each sample point. Points with a grid error of ±0.20 m were made transparent. [Click figure to enlarge.]

Error values representing the difference between the 30-m digital elevation model and the value at each sample point.
Figure 9. Error values representing the difference between the 30-m digital elevation model and the value at each sample point. Points with a grid error of ±0.20 m were made transparent. [Click figure to enlarge.]

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