Aggregation Methods Using Bathymetry Sources of Differing Subjective Reliabilities for Navigation Mapping

Abstract

When planning for ship navigation or compiling data for a bathymetry map, the navigator or mapper uses many different sources of bathymetry information and navigation hazards. The quality of these sources is inconsistent in general, however, making it challenging to provide a coherent picture for planning. Here, we describe an approach for consistent planning/mapping that uses a combination of soft computing and Bayesian estimation. The case study used to exercise this system involves NOAA Electronic Nautical Charts for an area in the Chesapeake Bay. We first interpolate each set of irregularly spaced soundings to gridded versions of each point-cloud set. Each of these intermediate grids is then aggregated into a fused bathymetric realization using order weighted averaging (OWA) to provide the weights for each source based on their subjective reliabilities. The OWA allows for fusion informed by the user’s subjective risk allowed in the reconstruction of the seafloor surface and provides quantitative methods to generate, use, and record subjective reliability weights. Each sounding point that went into the bathymetry estimate is then categorized as “no-go,” “caution,” or “go” status. Reliability estimates are reused for weighted Bayesian categorization of each output grid cell to compute the navigable surface.

Keywords:

• Bathymetry fusion
• Bayesian categorical estimation
• navigation risk
• order weighted average

Acknowledgments

The main authors wish to thank R. Wade Ladner, Raymond Sawyer, and Dr. David Fabre of the Naval Oceanographic Office and Brett Hode of the Naval Research Laboratory for their helpful discussions in the initial phase of research. The authors wish to thank all of the funding sources for their sponsorship of this research and the anonymous peer-reviewers for their guidance in revising this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data that support the findings of this study are openly available at https://nauticalcharts.noaa.gov/charts/noaa-enc.html.

Additional information

Funding

Initial funding for the conceptual development of this work was provided by the Office of Naval Research10.13039/100000006. Additional funding for generation of this paper was given to Elmore through a Janney grant of the Johns Hopkins University/Applied Physics Laboratory10.13039/100012314 and to Petry through the Naval Research Laboratory’s Base Program. Funding for Calder and Massetti was also provided by NOAA10.13039/100000192 grant NA20NOS4000196.