Important
Explore the maps, interactive 3D terrain and original high-resolution downloads at divetopo.com. The first published region is Réunion Island.
While preparing a trip to Réunion Island, I found it surprisingly difficult to locate detailed maps of its dive sites. Further research showed that useful public bathymetric, topographic and aerial data already existed, but was not easy to inspect together.
I downloaded and assembled these datasets to produce consistent 2D maps, static 3D perspectives, interactive terrain and printable sheets for a small, non-exhaustive selection of sites. DiveTopo now separates the reusable mapping engine and Web application from the sources and configurations of each region, so other regions can be added without copying the code.
Note
The codebase, website and original presentation were generated entirely with AI, under human direction, iterative visual review and validation against the source data. The geographic data comes from the public institutional sources listed below.
| Used for | Source | Role |
|---|---|---|
| Detailed seabed terrain | Ifremer HYSCORES 2015 | High-resolution bathymetry for the west-coast reef sectors, including the Litto3D additions distributed with HYSCORES |
| Land elevation | IGN RGE ALTI | Digital terrain model for the land surface |
| Aerial imagery | IGN BD ORTHO | Georeferenced imagery draped over land and, where configured, shallow water |
| Regional context | GEBCO 2024 | Generalized seabed relief for the locator and regional selection map |
Detailed Réunion processing uses WGS 84 / UTM zone 40S (EPSG:32740).
HYSCORES does not cover the whole island; a site outside its four published
sectors requires another numerical bathymetric source.
Each site configuration can produce:
- a north-up 2D map;
- a static oblique 3D perspective;
- topographic and aerial-imagery variants;
- a regional locator;
- two printable high-resolution sheets;
- a compact interactive 3D terrain package consumed by the website.
The seven current Réunion sites share 2474 × 1712 px static maps and
5400 × 3250 px printable sheets. Aerial imagery remains opaque down to
−1.5 m, fades to the bathymetric palette between −1.5 m and −2 m, and is
fully absent below −2 m. Isobaths are derived every 5 m.
| Site | Municipality | Configuration |
|---|---|---|
| Cap La Houssaye | Saint-Paul | cap-la-houssaye.json |
| Boucan Canot | Saint-Paul | boucan-canot.json |
| Passe de l'Hermitage | Saint-Paul | passe-hermitage.json |
| Cap Homard | Saint-Paul | cap-homard.json |
| Pointe au Sel | Saint-Leu | pointe-au-sel-sec-jaune.json |
| Pont Rouge | Saint-Leu | pont-rouge-la-tortue.json |
| Plage du Cimetière | Saint-Leu | plage-cimetiere-saint-leu.json |
| 2D map | Static 3D perspective |
|---|---|
 |
 |
These are lightweight previews. The website's download controls serve the canonical full-resolution JPEGs and sheets.
apps/web/ single Web application deployed at divetopo.com
cartography/ shared rendering, composition and terrain exporters
cartography/regions/ region-specific acquisition and orchestration
regions/<slug>/region.json regional identity, projection, sources and inventory
regions/<slug>/sites/ reproducible site configurations
regions/<slug>/outputs/ canonical generated cartographic artifacts
tests/ shared and regional contract tests
The website never generates terrain. It copies verified responsive derivatives from the canonical regional outputs. The interactive package format is documented in INTERACTIVE-TERRAIN.md.
Install the local macOS environment:
./bootstrap_macos.shValidate one configuration and its cached source rasters:
.venv/bin/python -m cartography.regions.reunion \
regions/reunion/sites/cap-la-houssaye.json --checkRefresh the official data and regenerate the maps:
.venv/bin/python -m cartography.regions.reunion \
regions/reunion/sites/cap-la-houssaye.json --refreshRebuild the printable sheets or the canonical interactive package:
.venv/bin/python -m cartography.plate \
regions/reunion/sites/cap-la-houssaye.json
.venv/bin/python -m cartography.interactiveThe shared rules are in WORKFLOW.md; source-specific parameters, all rendering controls and the full acceptance gate are in regions/reunion/WORKFLOW.md.
apps/web/ serves the general homepage and every regional route from one
deployment. Réunion is published under /reunion, with dedicated French and
English routes and indexable site routes below it. GitHub is the canonical
source; publishing the repository does not automatically deploy the hosted
site. See DEPLOYMENT.md.
- Original software: MIT.
- Réunion maps: CC BY-NC-SA 4.0, subject to the rights of their source datasets.
- Dataset licences and mandatory attributions: third-party notices.
The website and its content are free to access and contain no advertising. Maps help interpret terrain and general orientation. They do not establish access, authorization, present conditions or safety, and must not be used for navigation or as the sole basis of a decision affecting safety at sea.