A good fabrication preview should show both what the data supports and what needs your judgment. 3D Nautical Maps combines geographic sources with adjustments for a physical board. The result is decorative map artwork, not a certified nautical chart.
What data does the designer use?
- GMRT: topo-bathymetry grids supply elevation and water-depth samples used to form contours.
- NOAA ENC Direct: charted dredged-area depths supplement GMRT in covered U.S. harbors. These charted channel values are not live soundings; coverage and source dates vary. The designer shows whether this supplement was available.
- USGS and NOAA lake bathymetry: Tahoe maps use the 1998 USGS survey at 10 m grid spacing. All five Great Lakes and Lake St. Clair use NOAA compilations; Superior’s dataset is draft/incomplete. Depths use each dataset’s reference surface, not current water levels. The designer reports coverage; water outside the dataset remains flat.
- Optional illustrative lake depths: When a lake is the main subject and surveyed coverage is unavailable, you can explicitly choose estimated decorative layers based on its HydroLAKES outline and GLOBathy maximum-depth parameter. These follow distance from shore and can differ substantially from the actual lakebed, missing ridges, channels and off-centre basins. Nearby ponds on coastal maps are not automatically modeled. Available surveys take priority, and estimates are labeled in the designer and download. HydroLAKES (Messager et al., 2016) is CC BY 4.0; GLOBathy (Khazaei et al., 2022) parameters are CC0.
- Mapbox: location search and basemap services help you find and frame a place. The current primary shoreline workflow uses Mapbox water geometry to construct land and internal-water shapes.
- OpenStreetMap: source features support roads, place labels, points of interest, and water/coastline processing in fallback workflows.
The code also retains GMRT/OSM fallback paths. The source used can depend on data availability and the generation path. A visible feature on a basemap and a measured underwater contour are different kinds of information.
Why detail varies by location
Source resolution and coverage vary. Small waterways or islands can be generalized, and inland water may have a mapped boundary without detailed depth samples. The contour working target can interpolate existing measurements; it cannot add surveyed detail. No uniform depth accuracy or minimum feature resolution is promised.
Fabrication changes the representation
Board size, selected area, depth fitting, minimum island size, minimum land width, and waterway treatment affect the generated design. A small feature that is visible geographically may become fragile or disappear under an intentional size filter. Narrow waterways can be widened where safe or represented by engraving over solid material. Water-depth bands are a layered representation, not a continuous underwater surface.
What should you check?
Compare the selected region with your knowledge of the place. Review shoreline openings, detached islands, water bands, labels, and the final board dimensions. Inspect the individual layers as well as the assembled color preview, especially after applying geometry changes. If depth coverage does not support the map you want, choose another area or postpone that build.
For background on the underlying sources, visit USGS Lake Tahoe data, NOAA Great Lakes bathymetry, HydroLAKES, GLOBathy parameters, NOAA ENC Direct documentation, GMRT GridServer documentation, Mapbox Streets data documentation, and OpenStreetMap attribution and licensing. Use authoritative navigation products for navigation; these fabrication files are not a substitute.