Added Value to NOAA’s Bathymetry Products Kolleen Mortimer Edward Owens CDR Briana Hillstrom, NOAA CAPT Richard Brennan, NOAA Hydrographic Surveys Division

Challenge Examine in-house and commercial tools developed for automated generation of contours and soundings. Compare products created Traditional method using CARIS BASE Editor SCALGO’s Nautical Bathymetry module MCD’s DeriveNautical tool in ArcMap

Evaluation Criteria Assess sounding and contour generation at Band 4 and Band 5 scales Utilize Marine Chart Division's new contour intervals Review sounding improvement rules Test ability to create depth areas from generalized soundings Test constraint lines for preventing over generalization of contours Identify parameters that produce best results for differing seafloor characteristics

Data New York Rockaway Inlet Lower Bay Sandy Hook Bay

Traditional - Contouring Survey Scale Contours Generalized Contours

Traditional - Soundings Typically a combination of automated and manually selected soundings Considerations include: Current largest scale sounding density Surrounding chart soundings Junction survey soundings Seafloor morphology

Traditional - Analysis Hand digitization of contours was a manually intensive and subjective process. Contour technique was not sustainable for future products. While possible to create, depth areas frequently contained topological errors. There were a number of considerations when creating a sounding set: Was hydrography interpreted accurately? Were shoals, hazards, and safe passage highlighted? Were the soundings easy for the mariner to interpret?

SCALGO Nautical Bathymetry - Contouring Raw Contours Generalized Contours Depth Areas

SCALGO Nautical Bathymetry - Soundings User controlled input in options file: Shoals Deeps Critical soundings Cell size Distance from contour Density algorithms

SCALGO Nautical Bathymetry - Analysis Automated generalized contour creation with options for smoothing and small area contours. Topologically correct automated depth areas are created. Parameters can be modified for scale bands, contours, seafloor type, region, etc. Files are compatible with all mainstream GIS software. Soundings support and identify contours, channels and major features . Sounding density is modified for depth bands in the parameters file.

MCD’s DeriveNautical Soundings

Conclusions Traditional techniques used were tedious and left room for error. SCALGO’s Nautical Bathymetry presents an automated alternative to hand digitization. Topologically correct contours and depth areas created; not over generalized Soundings created, honored by contours, density easily modified More and more options coming to market What is the best tool for the job?

Thank you! Contact: Kolleen Mortimer kolleen.mortimer@noaa.gov