Europa/Nuvolari/docs/data-sources.md

Data sources

Every endpoint below was verified on 2026-09-10. Anything not verified is marked TO VERIFY and must not be relied on until checked.

1. Radar — Radar-DPC (default for the MVP)

Public platform of the Italian Dipartimento della Protezione Civile.

• Base URL: https://radar-api.protezionecivile.it/
• Transitional test base URL: https://wagiqofvnk.execute-api.eu-south-1.amazonaws.com/prod

GET /findLastProductByType?type=<PRODUCT>

Returns the timestamp of the most recent sample of a product.

{
  "total": 1,
  "lastProducts": [
    { "productType": "VMI", "time": 1758706200000, "period": "PT5M" }
  ]
}

• time is epoch milliseconds, UTC.
• period is the ISO-8601 cadence of the product.
• 400 when type is missing, 404 when no product is available.

POST /downloadProduct

Returns a pre-signed S3 URL for the raw raster file.

{ "productType": "VMI", "productDate": 1758706200000 }

{
  "bucket": "dpc-radar",
  "key": "VMI/22-09-2025-14-20.tif",
  "url": "https://dpc-radar.s3.eu-south-1.amazonaws.com/...",
  "expiresSeconds": 900
}

• productDate must be rounded down to the product step, otherwise 404.
• Pre-signed URLs expire after 300–900 s: download immediately, never cache the URL.
• 400 when productDate is missing or non-numeric.

Mandatory header

origin: https://radar.protezionecivile.it

Required on every request to the platform for security reasons; requests without it are rejected. Content-Type: application/json is also required on downloadProduct.

Products and cadence

Cadence	Products
5 min	VMI, SRI, SRT1, IR_108
30–60 min	TEMP, CUM3, CUM6, CUM12, CUM24, CAPPI_1…CAPPI_10, VIL, ETM, POH
—	SITES (GeoJSON, fetched directly from S3 with GET)

The MVP uses VMI (Vertical Maximum Intensity) as the precipitation layer. History retention is 14 days. Files are GeoTIFF; CRS is read from the file metadata rather than assumed — the worker reprojects to EPSG:3857 in all cases.

Raster format (read from a live VMI file, 2026-09-10)

Property	Value
Size	1200 × 1400 px
Pixel size	1000 × 1000 m — a 1 km grid
Bands / type	1 band, Float32, LZW compressed
Tie point	raster (0,0) → model (-600000, 650000)
Model type	projected, datum WGS84 (GeographicTypeGeoKey 4326)
Projection centre	12.5° E, 42.0° N (ProjCenterLong/ProjCenterLat)
Linear units	metre
Nodata tag	absent — expect NaN

The rasters are not in EPSG:4326 and not in EPSG:3857. They are on a custom projection centred on Italy, so reprojection to Web Mercator is mandatory, not an optimisation. The extent works out to 1200 km east-west and 1400 km north-south around that centre, which covers the whole country — the worker crops to the region bounding box before doing anything else, so it never carries the full mosaic through the pipeline.

The GeoKeys as written are internally inconsistent (ProjCoordTransGeoKey = 1, which is transverse Mercator, combined with the centre keys an azimuthal projection uses). Do not hardcode a source CRS. The worker reads the CRS from the file with rasterio and warps from whatever it finds, and logs the detected CRS on every run so a change at the source is visible instead of silently shifting the imagery.

Values are physical units (dBZ for VMI), not palette indices — the colour mapping is ours, and the legend that goes with it is published in the manifest.

Push channel

wss://radar-wss.protezionecivile.it pushes a notification whenever a new sample is published. The worker uses this as its primary trigger, with a 5-minute cron as a fallback, so we never poll DPC aggressively.

License

CC BY-SA. Attribution to "Radar-DPC" is mandatory and derived products must be released under the same license. The rendered PNG frames we publish are a derived product and inherit CC BY-SA.

Docs: https://dpc-radar.readthedocs.io/it/latest/

2. Radar — ARPA Piemonte (future adapter, disabled)

C-band polarimetric radars at Bric della Croce and Monte Settepani, HDF5 ODIM every 5 minutes. Access requires authorization requested at info.meteo@arpa.piemonte.it.

License CC BY 4.0, attribution "Fonte: Arpa Piemonte - www.arpa.piemonte.it".

ArpaRadarSource exists as a disabled stub. No request for authorization has been sent and none will be sent without an explicit instruction from the project owner.

3. Forecast — MET Norway

• https://api.met.no/weatherapi/locationforecast/2.0/compact?lat=<lat>&lon=<lon>
• A descriptive, identifying User-Agent is mandatory (application name plus a contact address). Requests with a generic or missing User-Agent are blocked.
• Honour Expires and use If-Modified-Since; do not re-request before expiry.
• License CC BY 4.0, commercial use allowed.

Fallback — ItaliaMeteo ICON-2I via MeteoHub

License CC BY 4.0, attribution "ItaliaMeteo-ARPAE". Endpoint details TO VERIFY before the adapter is enabled.

Explicitly excluded

Open-Meteo free tier — non-commercial only, and this app carries ads.

4. Alerts — ARPA Piemonte XML-CAP

• Feed: https://www.arpa.piemonte.it/export/xmlcap/allerta.xml
• Landing page: https://www.arpa.piemonte.it/rischi_naturali/snippets_arpa/allerta/index.html
• Official PDF bulletin: https://www.arpa.piemonte.it/rischi_naturali/boll/bollettino_allerta.pdf

Issued daily by 13:00 by the Centro Funzionale Regionale, 36 hours of validity.

Alert zones (11)

Piem-A … Piem-M (A, B, C, D, E, F, G, H, I, L, M), covering: Toce; Val Sesia/Cervo/ Chiusella; Valli Orco/Lanzo/bassa val Susa/Sangone; Alta val Susa/Chisone/Pellice/Po; Valli Varaita/Maira/Stura; Valle Tanaro; Belbo e Bormida; Scrivia; Pianura settentrionale; Pianura e colline torinesi; Pianura cuneese. The exact code-to-name mapping is stored in app/assets/regions/piemonte.json.

CAP document structure (verified against the live feed, 2026-09-10)

One <alert> contains one <info> block per zone; the zone is in info/area/areaDesc and holds the bare code (Piem-A), not a name.

<alert xmlns="urn:oasis:names:tc:emergency:cap:1.2">
  <identifier>261/2026</identifier>          <!-- bulletin number / year -->
  <sender>centro.funzionale@arpa.piemonte.it</sender>
  <sent>2026-09-09T10:00:02+00:00</sent>
  <status>Actual</status><msgType>Alert</msgType><scope>Public</scope>
  <note>AVVISO DI CONDIZIONI METEOROLOGICHE AVVERSE ...</note>
  <info>
    <event>GIALLO</event>                    <!-- overall level for this zone -->
    <onset>...</onset><expires>...</expires>
    <parameter><valueName>EFFETTI SUL TERRITORIO</valueName><value>...</value></parameter>
    <parameter><valueName>TEMPORALI_1224</valueName><value>GIALLO</value></parameter>
    <parameter><valueName>TEMPORALI_2436</valueName><value>VERDE</value></parameter>
    ...
    <area><areaDesc>Piem-A</areaDesc></area>
  </info>
  <!-- 10 more info blocks, one per zone -->
</alert>

Parameters are named <CATEGORY>_<WINDOW>:

• Categories — IDRAULICO, IDROGEOLOGICO, TEMPORALI, NEVE, VALANGHE.
• Windows — 1224 (hours 12–24) and 2436 (hours 24–36), matching the 36 hours of validity.

So each zone carries 10 level values plus one overall <event> level and a free-text EFFETTI SUL TERRITORIO.

Levels — six values, not four

Value	Meaning
VERDE	no significant phenomena
GIALLO	localised phenomena
ARANCIONE	widespread phenomena
ROSSO	numerous or extensive phenomena
BIANCO	avalanche scale only — outside the season / not assessed
-	no value published for that category and window

BIANCO and - are not "green with a different name" and must not be collapsed into it. The parser models the level as an enum with explicit bianco and notAvailable members, and the UI renders them as their own state rather than as "no alert".

Levels are republished verbatim, never reinterpreted, always alongside a link to the official bulletin. No license is stated on the ARPA page, so we credit ARPA Piemonte and link the source rather than claiming any reuse right.

Official bulletin PDF, linked from every alert view: https://www.arpa.piemonte.it/rischi_naturali/boll/bollettino_allerta.pdf

Zone codes

Piem-A … Piem-M, eleven zones: the Italian alphabet is used, so J and K do not exist — the sequence is A B C D E F G H I L M. The code-to-name mapping lives in app/assets/regions/piemonte.json; the human-readable names are not in the feed and come from the ARPA zone documentation.

A captured copy of the live feed is kept as a test fixture so the parser is verified against the real document rather than a hand-written approximation.

5. Municipalities — ISTAT

Piedmont municipality list to bundle in assets. Source TO VERIFY — the ISTAT "Codici statistici delle unità amministrative territoriali" dataset is the intended origin but the stable download URL has not been confirmed yet.

6. Base map — OpenStreetMap

Vector tiles via MapTiler (API key required, supplied through MAP_STYLE_URL) or self-hosted PMTiles. OSM/ODbL attribution must stay visible on the map at all times.

Until a key is configured the app falls back to a minimal local style so that development and tests run fully offline.

7. Lightning — excluded

Blitzortung must not be used: its data prohibits commercial use. If a lightning layer is ever added it will come from the DPC LTG product instead.