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

2. 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

3. 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

4. Data
New York
Rockaway Inlet
Lower Bay
Sandy Hook Bay

5. Traditional - Contouring
Survey Scale Contours
Generalized Contours

6. 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

7. 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?

8. SCALGO Nautical Bathymetry - Contouring
Raw Contours
Generalized Contours
Depth Areas

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

10. 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.

11. MCD’s DeriveNautical
Soundings

12. 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?

13. Thank you!
Contact: Kolleen Mortimer