Source Data
- Source: GEBCO 2026
- Source grid: 15 arc-second
Tile Projection
Bathymetry tiles are provided in Web Mercator (EPSG:3857).
Depth Levels
Available contour depth levels are 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180 and 200 m.
Zoom levels
Native bathymetric contour tiles are available from Z7 through Z13. Applications may overzoom Z13 tiles at higher zoom levels.
Higher zoom levels do not add additional bathymetric detail.
Interpolation and accuracy
Interpolation is used to smooth contour geometry for map display, but it does not improve the positional accuracy or underlying resolution of the source data.
Coastline alignment
Bathymetric contours may not align perfectly with every basemap. Visual differences may be more noticeable around small islands and complex shorelines.
1224Tools Bathymetry should not be interpreted as precise shoreline data or as a nautical chart.