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Europa/Nuvolari/docs/licenses.md
T
Alby96andClaude Opus 5 e14308bbb6 Survey the ARPA REST APIs and correct the licence position
Scanned the two public ARPA Piemonte APIs and recorded what they actually
contain, so this question does not get re-litigated from the marketing pages
later. Neither needs a key, a token or a registration.

This corrects something I got wrong. The docs said ARPA states no licence for
its data, based on the open-data page saying only "gratuiti". The site's legal
notice does state one — CC BY 4.0, commercial use explicitly permitted, credit
"Fonte: Arpa Piemonte - www.arpa.piemonte.it" — and both APIs link that notice
from their OpenAPI description, so anything they serve is covered. Only the
radar volumes remain ambiguous, because their own page does not repeat the
licence and the access link is still issued by email; both questions belong in
the same message to ARPA.

The survey's operative findings:

- api_realtime carries 374 stations with coordinates, of which 286 have a rain
  gauge, spanning 74 m to 2820 m of elevation.
- Its observations lag by about 4.5 hours on an hourly cadence, measured
  uniformly across every station sampled. That is the property that decides how
  it can be used: it is an observation archive with a publishing delay, not a
  real-time feed, and it must never sit next to 5-minute radar looking current.
- Only 4 of 143 hydrometer stations publish guard and danger thresholds, and 5
  publish a river name. A river-level warning built on this would be empty for
  97% of stations, so that idea is recorded as rejected rather than pending.
- Meteoweb is a 3.27-million-record historical archive plus a seismic
  catalogue: a research dataset, not app content.

One thing is worth adopting: rain-gauge accumulations as ground truth for the
radar. Radar infers rainfall from reflectivity aloft, gauges measure what
reached the ground, and the network is densest exactly where Alpine terrain
blocks the beam. It belongs behind the worker, clearly timestamped, once the
worker exists.

Also notes that the credit ARPA asks for is the full "Fonte: Arpa Piemonte -
www.arpa.piemonte.it", not the bare name currently in the region config, to be
adopted the moment any ARPA-sourced data is displayed.

No code changes: nothing is integrated yet.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-10 16:33:55 +02:00

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# Licenses and attribution obligations
Nuvolari redistributes third-party data. Every obligation below is binding: the
Sources screen in the app must satisfy all of them, and none of them may be dropped
to save screen space.
## Summary
| Data | License | Mandatory credit | Notes |
|---|---|---|---|
| Radar-DPC rasters | CC BY-SA | "Radar-DPC" | **Share-alike propagates to our frames** |
| ARPA Piemonte data | CC BY 4.0, commercial OK | "Fonte: Arpa Piemonte - www.arpa.piemonte.it" | Radar volumes: licence not repeated on their page, access by email |
| ARPA Piemonte alerts | CC BY 4.0 (site notice) | as above, + link to the official bulletin | Levels republished verbatim |
| OpenStreetMap data | ODbL | "© OpenStreetMap contributors" | Must stay visible on the map |
| OpenMapTiles schema | BSD 3-Clause | "© OpenMapTiles" | Must stay visible on the map |
| OpenFreeMap service | MIT | "OpenFreeMap" — optional | Listed on the Sources screen |
## Share-alike is the constraint that shapes the backend
The Radar-DPC rasters are **CC BY-SA**. The PNG frames the worker produces — cropped,
reprojected, colourised — are a derived product, so they inherit CC BY-SA. Practical
consequences:
- The published frames and `manifest.json` are CC BY-SA and must be labelled as such.
- We cannot relicense them, and we cannot restrict their reuse.
- The share-alike obligation covers the **data**, not the app's source code or UI.
The manifest carries its own `attribution` string for exactly this reason: the credit
travels with the frames rather than being remembered at render time, and the app
displays whatever the publisher of those frames says to display.
## ARPA Piemonte: CC BY 4.0, stated in the legal notice
ARPA's legal notice at <https://www.arpa.piemonte.it/note-legali> releases environmental
and open data under **CC BY 4.0**, explicitly permitting commercial use, and requires the
credit *"Fonte: Arpa Piemonte - www.arpa.piemonte.it"*. Logos, institutional emblems,
registered trademarks and third-party content are excluded.
Both ARPA REST APIs — `api_realtime` and Meteoweb — link that notice from their OpenAPI
`description`, so anything served by them is covered without further correspondence.
The **radar volumes** are the one gap: their open-data page says only *gratuiti* and does
not repeat the licence, and the real-time access link is issued by email. Ask ARPA to
confirm both in the same message. Until then the radar adapter stays disabled — see
[data-sources.md](data-sources.md) section 2.
The credit string ARPA asks for is the full *"Fonte: Arpa Piemonte -
www.arpa.piemonte.it"*, not the bare name currently in the region config. Adopt the full
form the moment any ARPA-sourced data is actually displayed.
## Base map credits are not automatic
The OpenFreeMap style JSON has no `attribution` field, so MapLibre displays nothing on
its own. The app renders the credits itself:
- the always-visible attribution bar carries the two **mandatory** credits;
- the Sources screen lists all three with their licences and links.
The bar lists only what is actually on screen. With the offline fallback style there is
no OpenStreetMap data being displayed, so crediting OpenStreetMap there would be a false
attribution — the bar says "Mappa base non configurata" instead.
## Advertising, and why it still matters here
The app currently carries **no advertising**, so it is not a commercial product today.
Ads are a plausible future, though, and a source adopted now on non-commercial terms
would have to be ripped out then. Prefer sources that permit commercial use.
This is why **Open-Meteo's free tier** and **Blitzortung** remain listed as excluded even
though the features that would have used them are out of scope: both are
non-commercial-only, and neither should be reached for on the grounds that there are no
ads at the moment.
## Naming and independence
The app must never appear to be an official ARPA or Protezione Civile product:
- no ARPA/DPC logos, coats of arms or institutional branding;
- never the word "ufficiale" applied to the app itself (the *bulletin* is official —
the *app* is not);
- the Sources screen carries an explicit disclaimer that Nuvolari is an independent
app, not affiliated with, endorsed by, or operated by ARPA Piemonte or the
Dipartimento della Protezione Civile;
- for civil-protection purposes the official channels always prevail, and the app
says so next to every alert.