Hydro Stations & Forest Fire Danger

Data sources

Hydro stations and discharge

• SPARQL endpoint: https://environment.ld.admin.ch/query
• Graph: <https://lindas.admin.ch/foen/hydro>
• For each station, the query returns:
  • Station URI and name
  • River URI and name
  • Latest discharge (via the FOEN hydro cube)
  • Dive suitability thresholds (ok_max, nogo_min) and alias names via SERVICE <https://api.openstuff.ch/sparql>
  • Geometry WKT (POINT(lon lat)) via geo:hasGeometry / geo:asWKT

Forest fire danger (regions)

• SPARQL endpoint: https://environment.ld.admin.ch/query
• Cube: <https://environment.ld.admin.ch/foen/gefahren-waldbrand-warnung/1>
• Graph: <https://lindas.admin.ch/foen/gefahren-waldbrand-warnung>
• For each forest fire warning region, the query returns:
  • Region URI and ID (e.g. https://ld.admin.ch/dimension/bgdi/biota/forestfirewarningregions/1805)
  • English region name
  • Latest fire danger level ID (1–5) from the cube
  • Canton URI, English canton name, and two‑letter abbreviation from <https://lindas.admin.ch/territorial> and <https://lindas.admin.ch/fso/register>
  • schema:validFrom timestamp of the latest observation

Region geometries (for spatial matching)

• GeoJSON is fetched from the geo.admin.ch MapServer: https://api3.geo.admin.ch/rest/services/api/MapServer/ch.bafu.gefahren-waldbrand_warnung/{regionId}?geometryFormat=geojson&sr=4326
• Each response contains a single Feature with:
  • geometry.type = "MultiPolygon" and its coordinates
  • Optional bbox for quick bounding‑box pre‑filtering
  • Properties such as name_*, title_*, valid_from, and canton, which are consistent with the cube data but are not relied on for logic

Client‑side logic

All logic runs in the browser; there is no server‑side code.

1. Fetch hydro stations
   • Posts the hydro SPARQL query to HYDRO_ENDPOINT.
   • Parses the JSON SPARQL results into station objects.
   • Extracts and parses station_geom_wkt into lon/lat using a small WKT POINT parser.
2. Fetch forest fire regions
   • Posts the fire‑regions SPARQL query to FIRE_ENDPOINT.
   • For each region, keeps: regionId, regionName, levelId (1–5), cantonName, cantonAbbr, and validFrom.
3. Fetch region geometries
   • For each region ID, requests GeoJSON from the MapServer.
   • Requests are parallelised with a small concurrency limit (default 8) to avoid overloading the service.
   • Stores a map regionId → { geometry, bbox }.
4. Spatial join: station → fire region
   • For each station with valid lon/lat:
     • Builds a point [lon, lat].
     • Iterates through regions:
       • If a region has a bbox, first checks if the point lies inside that box.
       • Runs a point‑in‑polygon test against the MultiPolygon geometry:
       • Uses a standard ray‑casting algorithm for each linear ring.
       • Outer ring must contain the point; inner rings (holes) must not.
     • On the first match, attaches a fire object to the station with regionId, regionName, levelId, cantonName, cantonAbbr, and validFrom.
5. Dive suitability status
   • Reuses the same logic as stations-by-river.html:
   • Computes a status (ok, caution, nogo, unknown) from discharge, okMax, and nogoMin.
   • Renders a coloured status dot with an explanatory tooltip.

Rendering and UI

• Stations are grouped by riverName and sorted by stationName, as in stations-by-river.html.
• Each list entry shows:
  • Dive status dot (if available).
  • Link to station-detail.html?station=….
  • FOEN station link (entry.stationUri) in parentheses.
  • Optional divesite aliases (“· Divesites: …”) from the assessment service.
  • A per‑station fire danger chip, if a forest fire region was matched, e.g. · Fire: Low danger (SO).
• Fire danger labels and colours follow the FOEN scale:
  • Level 1 — Low danger — #ccff66
  • Level 2 — Moderate danger — #ffff00
  • Level 3 — Considerable danger — #ff9900
  • Level 4 — High danger — #ff0000
  • Level 5 — Very high danger — #800000
• The fire danger chip has a tooltip such as:
  Forest fire danger as of 2025-11-17T12:01:11+01:00 in Dorneck / Thierstein (SO)

Disclaimers

• Dive suitability: the suitability assessments are manually curated for some stations and are indicative only. Conditions can change rapidly; always assess on site and follow local regulations. No warranty; use at your own risk.
• Forest fire danger: values are derived from the FOEN forest fire warning dataset and linked to stations by spatial overlay in the browser. Official cantonal guidance always takes precedence; no warranty is given.