# 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 radar | CC BY 4.0 | "Fonte: Arpa Piemonte - www.arpa.piemonte.it" | Adapter disabled, unused |
| MET Norway forecast | CC BY 4.0 | "MET Norway" | Identifying User-Agent required |
| ItaliaMeteo ICON-2I | CC BY 4.0 | "ItaliaMeteo-ARPAE" | Fallback, behind a flag |
| ARPA Piemonte alerts | not stated | "Arpa Piemonte" + link to the official bulletin | Levels republished verbatim |
| OpenStreetMap base map | ODbL | "© OpenStreetMap contributors" | Must stay visible on the map |

## 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.

## MET Norway User-Agent

MET Norway blocks generic User-Agent strings. Requests must carry an identifying
string with a real contact address:

```
Nuvolari/<version> (<contact address>)
```

The contact comes from `METNO_USER_AGENT_CONTACT` in `env.json` and is never hardcoded.
The `Expires` header must be honoured — re-requesting before expiry risks a block.

## Not usable

- **Blitzortung** — commercial use prohibited. This app carries ads, so it is
  commercial. Never integrate it.
- **Open-Meteo free tier** — non-commercial only. Same reasoning.

## 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.