Data build scripts

One-off / occasional scripts that fetch source data and produce the maps/data/* and data/* artifacts the site ships. Run them from the repo root, e.g. python3 tools/build-stream-metrics.py.

External dependencies

Tool	Needed by	Install
`python3`	all `*.py` builders	system
`node`	all `*.js` builders	system
`tippecanoe`	`build-stream-metrics.py` (vector-tiles the gradient/width overlay)	`brew install tippecanoe`

tippecanoe turns GeoJSON into .pmtiles vector tiles. It is required to regenerate maps/data/kootenay-stream-metrics.pmtiles; the map loads that file via the pmtiles protocol so the browser only downloads the tiles in view. (The existing fwa-streams.pmtiles / beats-basin.pmtiles are also vector tiles but were produced outside this repo.)

Map-data builders

Script	Output	Source
`build-drift-suitability.py`	`kootenay-drift-suitability.geojson`	American Whitewater GraphQL (whitewater ratings overlay)
`build-stream-metrics.py`	`kootenay-stream-metrics.pmtiles`	bcfishpass `streams_vw` (per-segment gradient, channel width, mean annual flow) → tiled with tippecanoe
`build-canyon-hazards.py`	`kootenay-canyon-hazards.geojson`	bcfishpass `streams_vw` (order 5+) scored with SRTM wall-rise via `dem.py` — canyon-confinement hazard tiers (amber ≥40 m, red ≥80 m, validated against American Whitewater grades); first run caches ~230 MB of DEM tiles in `raw/dem/`
`build-classified-waters.py`	`kootenay-classified-waters.geojson`	B.C. Reg. 125/90 classified waters
`build-stocking.js`	`kootenay-stocking.geojson`	FFSBC stocking records
`build-lake-catalog.js`	`lake-catalog.json`	lake catalogue

See each script's module docstring/header for parameters (bounding box, filters, etc.).