Dataset Reference¶

pywmp.datasets provides automated downloaders for all spatial inputs required by a watershed model.

DatasetManager¶

The DatasetManager controls the download order, caching, and summary of downloaded files.

Basic usage¶

from pywmp.datasets import DatasetManager

dm = DatasetManager(
    aoi=(-81.700, 27.850, -81.500, 27.950),
    output_dir="data/my_watershed",
)

dm.download_dem(resolution_m=10)
dm.download_watershed(huc_level=12)
dm.download_nhd()
dm.download_nlcd(year=2021)
dm.download_soils()
dm.download_cn()
dm.download_atlas14(lat=27.9, lon=-81.6)
dm.download_floodzone()
print(dm.summary())

Datasets supported¶

download_dem() — USGS 3DEP DEM data at selectable resolution
download_watershed() — USGS Watershed Boundary Dataset (WBD)
download_nhd() — NHD flowlines and catchment polygons
download_nlcd() — NLCD land cover raster
download_soils() — USDA SSURGO soil and HSG raster data
download_cn() — derive a curve number raster from NLCD + SSURGO
download_atlas14() — NOAA Atlas 14 IDF curves for a point location
download_floodzone() — FEMA NFHL flood zone polygons

Workflow notes¶

Download the DEM first. Many other dataset downloaders use the DEM footprint or AOI geometry.
Download NLCD and soils before calling download_cn().
download_all() runs all supported downloaders in a sensible sequence.

Output files¶

The dataset manager writes files into output_dir. Typical outputs include:

dem.tif
watershed.gpkg
nhd_flowlines.gpkg
nhd_catchments.gpkg
nlcd.tif
soils.tif
cn.tif
atlas14_idf.json
floodzone.gpkg

Troubleshooting downloads¶

If a dataset is not available for the AOI, try a nearby location or a larger AOI.
If download requests fail, check internet access and firewall settings.
For large AOIs, use coarser DEM resolution and download data incrementally.