Eliminates the external wgrib2 C tool dependency that blocked HRRR
processing. Implements Lambert Conformal projection, simple packing
(Template 5.0), complex packing with spatial differencing (Template 5.3),
and GRIB2 section parsing — enough to extract point values from HRRR
grid data using only Elixir.
Fetch elevation data along the path between two stations via the
Open-Meteo Elevation API (with Open-Topo-Data fallback), compute
Fresnel zone clearance, earth bulge, and knife-edge diffraction loss,
and store the results per QSO.
- terrain_profiles table with migration and TerrainProfile schema
- ElevationClient with batched API calls and fallback
- TerrainAnalysis with Fresnel/diffraction physics (ITU-R P.526-15)
- TerrainProfileWorker on Oban :terrain queue
- QsoWeatherEnqueueWorker enqueues terrain jobs automatically
- QSO show page displays verdict badge and collapsible elevation table
- Reorder show page: terrain, soundings, solar, HRRR, surface obs
- Fix Dockerfile wgrib2 build (add cmake dependency)
IEM was returning 503s under 10 concurrent workers. Three fixes:
- Req transient retry with exponential backoff on IEM requests
- WeatherFetchWorker Oban job retries failed ASOS/RAOB fetches 2-3h later
with random jitter to avoid thundering herd
- Import script concurrency reduced 10→5, weather queue capped at 3
