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San Juan bathymetry atlas

A fixed view beneath the islands: real GEBCO depth values on water-clipped H3 grids. The detailed R8 map and coarser R6 inset share one extent and depth scale.

Beneath the San Juans: H3 R8 mean bathymetry, an R6 comparison inset, island labels, scale bar and shared 0–400 metre depth legend. Gray cells retain unavailable depth.

Open full-resolution PNG Download print PDF

Read the map

Darker cells show deeper mean water depth. The fine grid reveals variation through Haro Strait and the surrounding island passages; the inset shows the same area in larger cells. Each color is an existing product's cell mean. Rendering adds no smoothing, interpolation or replacement of missing values. Cells at the map edge are visually clipped; their values are not recomputed.

Gray means depth unavailable, not zero or dry land. Pale land comes from a generalized coastline, so small islands and narrow channels may be simplified. The 5 km scale bar uses the map's UTM projection. Place labels are editorial orientation aids, not an authoritative gazetteer.

Displayed support H3 R8 · main map H3 R6 · inset
Cells intersecting this view 2,562 80
Cells with mean depth 2,420 79
Cells retaining null depth 142 1
Available cell means 1–354 m 10.70–243.43 m

Counts describe the displayed crop, not the full source grid or surveyed area. R6 and R8 are distinct sampling supports; the inset is not a resampled image of the main map.

A snapshot, with its provenance intact

The tables were produced on September 19, 2026, in the exploratory San Juan notebook workspace. This illustration was exported on October 4, 2026. It freezes those historical outputs; it does not claim a current-method rebuild, a complete audited regional release, or independent scientific validation. The source raster, products, upstream references and geometry identities were checked before rendering. The later pilot's temporary products were not substituted.

Depth: GEBCO Compilation Group (2026), GEBCO 2026 Grid, DOI 10.5285/4f68d5c7-45eb-f999-e063-7086abc036fa. Its 15 arc-second grid spacing does not establish uniform survey resolution or accuracy. The cached raster records elevation relative to sea level; output means are metres positive down. Display projection: WGS 84 / UTM zone 10N.

Land: Natural Earth v5.1.1 at 1:10 million cartographic scale. Both providers place these data in the public domain; source acknowledgement and provider terms apply. See GEBCO terms and Natural Earth terms. The historical manifest's older license label has not been rewritten. Not for navigation. No provider endorsement is implied.

Reproduce this exact export

The renderer requires the retained notebook workspace and extracted Natural Earth cache. It refuses different product or geometry identities, verifies manifest checksums, and joins by unique H3_INDEX. Missing inputs fail; there is no download fallback.

From the checkout with the Seascape runtime installed:

MPLCONFIGDIR=/tmp/seascape-map-mpl python scripts/render_san_juan_snapshot.py \
  --workspace notebooks/outputs \
  --land notebooks/outputs/data/raw/natural_earth/ne_10m_land/ne_10m_land.shp \
  --output docs/assets/san-juan-snapshot.png

Outputs are the PNG, print PDF and adjacent identity record. The record stores source and output checksums, crop, projection, scale and missingness counts. Cached scientific inputs are not bundled with this page. Rendering leaves their values and historical manifests unchanged.

For a runnable example without regional inputs, use Read and verify a bathymetry result. For broader source context and subsequent validation, see the San Juan pilot.