An ocean floor map is bathymetry pointed at the sea: the continental shelf, the drop-off, and the deep water around a coastline, drawn as depth contours and cut into a layered relief. It reads like a vintage nautical chart given physical height - shallow reef water on top, the shelf stepping down through teals, and the deep navy floor at the bottom.

This guide uses the free Coastal Depth Chart preset on MyLaserTools, which pulls real public ocean bathymetry so coverage is global. For lakes, see our bathymetric lake map guide.

What You’ll Need

Item Notes
5 sheets of 3 mm laser ply The five depth bands
1 backplate sheet Stained or painted deep navy
Or 5 shades of blue acrylic Colour reads the depth
Optional clear epoxy For a glassy “water” finish

Step 1: Frame a Coast With a Real Drop-Off

Open the Coastal Depth Chart preset. It loads on Australia ringed by its seas. Search your coast and zoom so the shoreline and surrounding water both fit with a margin.

The key is choosing a spot with a real drop-off. Ocean bathymetry is coarse very close to shore, so pick an island, a bay, a reef, or steep continental shelf where the depth actually changes:

Great Subjects Why
Haida Gwaii, Vancouver Island Steep Pacific shelf
Bay of Fundy, Cape Breton Dramatic Atlantic coast
Hawaii, a Caribbean reef Volcanic and reef drop-offs
A Norwegian fjord mouth Deep water meeting cliffs

If the preview shows flat water with no bands, the sea floor is too uniform there - nudge to a steeper coast.

Step 2: Tune the Depth Bands

Group Role
Ocean depth (5 bands) Bathymetry with water cut as holes; each band a plate with deeper water removed. Band 1 is the visible top face (shallowest water at the shoreline)
Backplate Deep navy, the deepest water

Unlike a lake chart, there’s no separate land shore plate - the shoreline is simply the edge of band 1. If your scene includes land you want to read as land, add a solid land layer in a sand or stone tone on top.

Step 3: Export and Assemble

  • Export the per-layer SVG ZIP; keep inversion/holes ON; turn on small-polygon cleanup.
  • Cut the backplate first (or a deep teal so the deepest water glows), then the five bands deepest to shallowest.
  • Dry-fit, glue bottom-up, weight flat, and sand the outer edges flush.
  • For the showpiece version, pour a thin layer of clear epoxy over the assembled basin so the stepped sea floor sits under glassy “water.”

Make It Yours

  • Cut the bands from successively darker blue acrylics and skip painting entirely.
  • Engrave the place name and a depth scale into a band or caption plate.
  • Mark a dive site, wreck, or snorkelling spot with a small icon on band 1.
  • Pair it with a coastal city map of the same shoreline for a land-and-sea diptych.

For the tool’s own walkthrough, see the MyLaserTools ocean floor guide.

Free for commercial use - coastal depth charts are a natural fit for maritime and tourist-town markets.