toporama — keyless edition (experimental)

Same 3D-printable raised-relief map generator as the web/ version, but with no API key, no billing, and no sign-up. A visitor just opens the page and starts drawing. This is a parallel build — the Google-based web/ version is untouched and still works.

How it's keyless

Concern	web/ (Google)	web-keyless/ (this)
Base map	Google Maps JS (key + billing)	Leaflet + OpenStreetMap raster tiles
Elevation	Google Elevation API (key + billing)	AWS Terrain Tiles (elevation-tiles-prod, no key)
Box drawing	Google overlay + drag	Leaflet rectangle + drag
Everything else	shared topocore.js / worker.js	identical (copied unchanged)

Elevation comes from AWS's open "terrarium" PNG tiles: each pixel encodes a height in metres as (R*256 + G + B/256) - 32768. elevation.js picks a zoom whose pixels are ~4× finer than your build grid (so each sampled point comes from well-resolved data rather than a pre-smoothed tile — this is what makes the detail match a paid elevation service), capped at a 160-tile download budget so large areas stay bounded. It fetches only the tiles covering your box, decodes them on a canvas, and bilinearly samples every grid point.

Run it locally

cd web-keyless
python3 -m http.server 8000
# open http://localhost:8000

No key prompt — draw a box (or type coordinates under Advanced options), set a width, and hit BUILD.

Deploy for others

Static files, same as the Google version — drop the folder on GitHub Pages, Netlify Drop, or Cloudflare Pages. Because there's no key at all, there's nothing to restrict or protect; anyone can use the deployed URL directly.

Tradeoffs vs. the Google version

• Data resolution. Terrain tiles are built from public DEMs (SRTM and friends), roughly 30 m in many places and finer in the US, maxing out at zoom 15 (~3–5 m/px). Plenty for a printed relief model, but not the on-demand high-precision point sampling Google can do in some regions.
• OpenStreetMap tile policy. The base map uses tile.openstreetmap.org, whose usage policy is fine for personal/experimental use but discourages heavy production traffic. For a popular public deploy, switch the OSM_STYLE tiles URL in app.js to a proper tile provider (many have generous free tiers) or a vector-tile basemap.
• Box editing. After drawing, "redraw" replaces the box (there are no drag handles to resize it in place yet). The lat/long entry covers precise boxes.

Tests

node test/smoke.mjs

Stubs Leaflet + three.js and injects a synthetic terrarium tile, then drives the app through drag-draw, coordinate entry, validation, build, and STL download. The terrarium decode and slippy-tile math are additionally verified by round-trip. Real AWS-tile fetching (CORS, PNG decode) is verified live in a real browser, since the sandbox network blocks the tile host.