Accessing National Flood Hazard Layers (NFHL) through web services.

Module Contents#

class pygeohydro.nfhl.NFHL(service, layer, outfields='*', crs=4326)#

Access National Flood Hazard Layers (NFHL).

  • service (str) – The service type. Valid services are:

    • NFHL: Effective National Flood Hazard Layers

    • Prelim_CSLF: Preliminary Changes Since Last Firm (CSLF)

    • Draft_CSLF: Draft Changes Since Last Firm (CSLF)

    • Prelim_NFHL: Preliminary National Flood Hazard Layers

    • Pending_NFHL: Pending National Flood Hazard Layers

    • Draft_NFHL: Draft National Flood Hazard Layers

  • layer (str) – A valid service layer. Valid layers are service specific:

    • NFHL: nfhl availability, firm panels, lomrs, lomas,

      political jurisdictions, profile baselines, water lines, cross-sections, base flood elevations, levees, seclusion boundaries, coastal transects, transect baselines, general structures, river mile markers, water areas, plss, limit of moderate wave action, flood hazard boundaries, flood hazard zones, primary frontal dunes, base index, topographic low confidence areas, datum conversion points, coastal gages, gages, nodes, high water marks, station start points, hydrologic reaches, alluvial fans, and subbasins

    • Prelim_CSLF: preliminary, coastal high hazard area change,

      floodway change, special flood hazard area change, and non-special flood hazard area change

    • Draft_CSLF: draft, coastal high hazard area change,

      floodway change, special flood hazard area change, and non-special flood hazard area change

    • Prelim_NFHL: preliminary data availability,

      preliminary firm panel index, preliminary plss, preliminary topographic low confidence areas, preliminary river mile markers, preliminary datum conversion points, preliminary coastal gages, preliminary gages, preliminary nodes, preliminary high water marks, preliminary station start points, preliminary cross-sections, preliminary coastal transects, preliminary base flood elevations, preliminary profile baselines, preliminary transect baselines, preliminary limit of moderate wave action, preliminary water lines, preliminary political jurisdictions, preliminary levees, preliminary general structures, preliminary primary frontal dunes, preliminary hydrologic reaches, preliminary flood hazard boundaries, preliminary flood hazard zones, preliminary submittal information, preliminary alluvial fans, preliminary subbasins, and preliminary water areas

    • Pending_NFHL: pending submittal information, pending water areas,

      pending firm panel index, pending data availability, pending firm panels, pending political jurisdictions, pending profile baselines, pending water lines, pending cross-sections, pending base flood elevations, pending levees, pending seclusion boundaries, pending coastal transects, pending transect baselines, pending general structures, pending river mile markers, pending plss, pending limit of moderate wave action, pending flood hazard boundaries, pending flood hazard zones, pending primary frontal dunes, pending topographic low confidence areas, pending datum conversion points, pending coastal gages, pending gages, pending nodes, pending high water marks, pending station start points, pending hydrologic reaches, pending alluvial fans, and pending subbasins

    • Draft_NFHL: draft data availability, draft firm panels,

      draft political jurisdictions, draft profile baselines, draft water lines, draft cross-sections, draft base flood elevations, draft levees, draft submittal info, draft coastal transects, draft transect baselines, draft general structures, draft limit of moderate wave action, draft flood hazard boundaries, and draft flood hazard zones

  • outfields (str or list, optional) – Target field name(s), default to “*” i.e., all the fields.

  • crs (str, int, or pyproj.CRS, optional) – Target spatial reference of output, default to EPSG:4326.


>>> from pygeohydro import NFHL
>>> nfhl = NFHL("NFHL", "cross-sections")
>>> gdf_xs = nfhl.bygeom((-73.42, 43.28, -72.9, 43.52), geo_crs=4269)



A dictionary of valid services and their URLs.



bygeom(geom, geo_crs=4326, sql_clause='', distance=None, return_m=False, return_geom=True)#

Get features within a geometry that can be combined with a SQL where clause.

byids(field, fids, return_m=False, return_geom=True)#

Get features by object IDs.

bysql(sql_clause, return_m=False, return_geom=True)#

Get features using a valid SQL 92 WHERE clause.