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>
Alby96andClaude Opus 5
e14308bbb6