# Ground plates — sources, licences, access dates

Every pixel of `ground-*.png` is computed from the sources below by `scripts/land/plate.py`. Nothing is painted by hand.

| Layer | Source | Licence | Accessed |
|---|---|---|---|
| Relief (elevation) | AWS Terrain Tiles, terrarium encoding, z10 (80 tiles, x 532–541, y 360–367) — `https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png` | Public/open: Mapzen/Tilezen terrain tiles aggregate SRTM (NASA, public domain), EU-DEM (Copernicus), swissALTI3D-derived and other open sources; attribution per [tilezen/joerd attribution](https://github.com/tilezen/joerd/blob/master/docs/attribution.md) | 2026-09-27 (this session's cache) |
| Relief, higher resolution | Same service, z11 mosaic 8.26–11.07 E, 45.09–46.44 N (`dem-z11.f32`, brainstorm 3361578) | as above | 2026-09-20 |
| Night lights | NASA Black Marble 2016 (VIIRS Day/Night Band), GIBS WMTS EPSG:4326 level 7 tiles rows 19–20, cols 83–84 — `https://gibs.earthdata.nasa.gov/wmts/epsg4326/best/VIIRS_Black_Marble/default/2016-01-01/500m/{z}/{row}/{col}.png` | NASA imagery, public domain; credit "NASA Earth Observatory / NASA EOSDIS GIBS" | 2026-09-27 |
| Lakes | OpenStreetMap: 13 lake relations (Como, Lugano, Maggiore, Varese, Orta, Comabbio, Pusiano, Annone, Mergozzo, Iseo, Endine, Idro, Garda) via Overpass | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-20 |
| Smaller lakes | OpenStreetMap `natural=water` + `water=lake/reservoir` in 45.10–46.27 N, 8.34–11.02 E (`region-water.json`, Overpass data timestamp 2026-09-21T11:39Z) | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-21 |
| Rivers | OpenStreetMap relations/ways for Adda, Brembo, Lambro, Oglio, Olona, Po, Seveso, Ticino | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-20 |
| Border | OpenStreetMap relation 51701 ways "Italia – Schweiz" in the region (`region-border.json`, 2026-09-21) plus the western ways (`way[boundary=administrative][admin_level=2](45.80,7.60,46.50,8.60)` from `https://overpass-api.de/api/interpreter`, data timestamp 2026-09-27T20:41:49Z) | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-21 and 2026-09-27 |
| Town lights (points) | OpenStreetMap `node[place~city|town|village](45.05,7.60,46.95,10.60)` — 3 933 nodes from `https://overpass-api.de/api/interpreter`, data timestamp 2026-09-27T20:58:06Z; each carries the brightest Black Marble luma within ~750 m, and only lit ones (luma ≥ 0.12 after the land floor) are drawn | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-27 |
| Pins: offices | ComoNExT, Via Cavour 2, Lomazzo — OSM node 11349111498 (via Nominatim); Via Carlo Goldoni 1, Milano — interpolated from OSM address nodes 11–21 (±40 m), Nominatim has no housenumber 1 inside Milano | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-21 |
| Pins: towns | OSM place nodes (Como, Lugano, Varese, Lecco, Bergamo, Monza) from `region-places.json` | © OpenStreetMap contributors, ODbL 1.0 | 2026-09-21 |
| Pins: peaks | 18 named summits and heights listed in `work/panorama.mjs` (brainstorm 2585728), copied to `scripts/land/places.json` | editorial list; positions checked against the DEM (pin placed at the DEM top within 300 m) | 2026-09-24 |
| Moon and sun | Computed with PyEphem for 45.6974 N 9.0356 E, 2019-05-17 19:30 UTC: moon az 132.2°, alt 19.2°, 98.4 % lit; sun az 306.7°, alt −6.6° | PyEphem (MIT) | 2026-09-27 |
| Colours | `src/design/pigmenti.css` (night, oltremare, indaco, glacier, biacca, oro, light-core, sinopia, incarnato) | project | — |

Treatments that are not observations, stated so no one mistakes them for data:

- **Snow** (finish A) is a mid-May rule, not a satellite snow map: cover rises from 1900 to 2500 m, about 250 m lower on
  north faces, shed from slopes steeper than ~45°.
- **Albedo** is uniform per elevation band (plain/wood vs. rock above ~1500–2200 m); there is no land-cover layer.
- **Lake reflections** of shore lights are vertical glitter drawn below real Black Marble maxima within ~1 km of a lake.
- **Vertical exaggeration** is 2.0×; the projection is a bent (Berann-style) panorama, not a photograph.

Required on-screen credit wherever a plate is shown: `Relief: AWS Terrain Tiles · Lights: NASA Black Marble ·
Map data © OpenStreetMap contributors (ODbL)`.