# Cross-filter review Findings that affect more than one filter. Each finding lives in exactly one review file; the filter reviews it affects link here and record only how it applied to them. Findings keep their numbers across all review files, and new findings take the next number wherever they are filed. A finding that turns out to affect other filters moves here, leaving a link behind. ## Findings **2. Base NOAA aggregation is not area-weighted.** Every touched raster cell receives equal weight, including cells that intersect only a small portion of a county. This can matter most for small or narrow counties and along coastlines. *Resolved for Köppen on 2026-09-13: class shares are now area-weighted ([filter-calculations.md](../filter-calculations.md) §1).* Affects filters 1 (resolved), 2, 6, and 7. **11. Spatial weighting is inconsistent across metric families.** Base NOAA normals use equal touched-cell weights, Köppen uses area-weighted class shares, gridMET humidity uses \(\cos(\phi)\) weights on cell centers, and NSRDB polygon metrics use estimated overlap areas. Cross-metric comparisons should account for these different county aggregation methods. Affects filters 1, 2, 6, 7, 10, 11, and 12. The planned fix is item 3 of the target design in [pipeline-plan.md](../pipeline-plan.md): one shared county-aggregation module used by every raster-based metric. **12. Alaska and Hawaii are not covered by the NOAA and gridMET sources.** NOAA nClimGrid and gridMET cover the contiguous U.S. only; the nClimGrid grid spans latitude 24.56 to 49.35 and longitude −124.69 to −67.02. All 29 Alaska and 5 Hawaii counties are therefore blank in filters 2–10. Solar GHI and clear-sky reduction (filters 11 and 12) cover both states. `check_climate_data.py` allows these blanks (`OUTSIDE_CONUS`). The notes on the base build in `scripts/county_data_sources.md` say "fallback values are applied" for counties outside NOAA coverage, but `build_county_climate_data.py` leaves them blank (lines 499–520). Affects filters 2–10. Open decision: "Alaska and Hawaii coverage" in [decisions.md](../decisions.md). **13. Lexington, VA (51678) is missing from the NOAA daily county files.** Diurnal temperature range and extreme temperature days are blank for it, and `check_climate_data.py` allows those blanks (`NOAA_DAILY_MISSING_FIPS`). Heat-index days instead use the surrounding Rockbridge County (51163) as a proxy, recorded in `humidHeatSourceFips` and `humidHeatFipsAdjustment`. The three filters handle the same gap differently. Affects filters 3, 4, and 5. **14. Helper functions are duplicated across scripts, and some copies have drifted.** A 2026-09-13 survey found 19 functions with identical copies in several scripts and 19 with copies that have drifted apart. Most identical copies are NSRDB helpers, which belong in an NSRDB module rather than `common/`; `read_csv_rows` (4 identical copies in `apply_*` scripts) is cross-source. Drifted copies need a decision on which version is correct before merging. Notable drifts: `summarize_county_gridmet_humidity.py` has its own county loader and FIPS normalizer, and the state FIPS table is also copied in `build_county_representative_points.py`, `summarize_county_gridmet_humidity.py`, and `request_nsrdb_county_polygon_archives.py`. Affects every script that holds a copy. The rules for moving shared code are in [scripts/common/README.md](../../scripts/common/README.md). **15. The app's source text for three NOAA metrics names the wrong product.** In `app.js`, `avgTempF`, `annualPrecipIn`, and `seasonalityIndex` credit "NOAA NCEI 1991-2020 U.S. Climate Normals" and link the station-based Normals page. Their values are computed from the nClimGrid-Monthly series averaged over 1991–2020, which is NCEI's gridded-normals method rather than the station product. Source 2 in `scripts/county_data_sources.md` likewise says the build reads monthly normals files, while the build command passes `data/noaa/nclimgrid/nclimgrid_tavg.nc` and `nclimgrid_prcp.nc`. Found during the filter 2 review (2026-09-15). Affects filters 2, 6, and 7. Filter 2's task list covers the `avgTempF` text. **16. Source links point to retired or missing pages.** Checked 2026-09-15. In `app.js`, the "NOAA nClimGrid Monthly" link used by wettest and driest month (`https://www.ncei.noaa.gov/products/land-based-station/nclimgrid`) returns 404, and the "NREL National Solar Radiation Database" link used by solar GHI and clear-sky GHI reduction (`https://nsrdb.nrel.gov/`) no longer resolves. NREL's sites have moved to `nlr.gov`: `https://nsrdb.nlr.gov/` loads, and the NSRDB scripts already call `developer.nlr.gov`. In Source 4 of `scripts/county_data_sources.md`, `https://developer.nrel.gov/docs/solar/nsrdb/` also fails (its `developer.nlr.gov` counterpart loads), and `https://www.nrel.gov/gis/solar-resource-maps` fails with no counterpart at the same path on `nlr.gov`. Every other link in `app.js`, `README.md`, and `scripts/county_data_sources.md` loads. Affects filters 8, 9, 11, and 12. **17. The data-sources metric list is out of date.** The "Metric definitions in generated output" list in `scripts/county_data_sources.md` describes `extremeDays` / `oldExtremeDays` as an audit column kept in the app CSV, but neither column is in `data/climate-data.csv`. The list has no entry for `avgDiurnalTempRangeF` or `absoluteExtremeDays`, 2 of the 12 app metrics. Affects filters 3 and 4. ## Decisions In [decisions.md](../decisions.md): Shared helpers (2026-09-13), and the open decision on Alaska and Hawaii coverage. ## Tasks Fixes for these findings are carried out in the affected filters' reviews. ## Original review `filter-calculations.md` was derived from the checked-in calculation and merge scripts, not solely from UI descriptions. No calculation code was changed. The automated test suite was not executed during this review because `pytest` is not installed in either the system Python environment or the project virtual environment. The suite uses `unittest` and runs without pytest: `python -m unittest discover -s tests`. Section 1 and findings 2, 4, and 11 were updated on 2026-09-14, after the Köppen classification was reworked and applied.