StreamSegmentNHD
StreamSegmentNHD is a class object that represents a stream segment
in the NHDPlusV2.1. It is built for easy access to a single stream
segment represented by a ComID without overburdening memory. It is
meant for the NHDPlusV21_National_Seamless_Flattened_Lower48.gdb. It
also requires a ComID dictionary used as a map, which can be found at
s3://nwm-datasets/Data/Vector/NHDPlusV21_CONUS_seamless/comidDict_NHDPlusV21.json
or can be made using fiona like so:
gdb = 'NHDPlusV21_National_Seamless_Flattened_Lower48.gdb'
src = fiona.open(gdb, layer='NHDFlowline_Network')
comidDict = {src[f]['properties']['COMID']: k for k in src.keys()}
StreamSegmentNHD(self, comid: int, comidDict: dict, src: fiona.collection, warning: bool = True)
A representation of one individual NHDPlusV2.1 ComID stream segment.
For detailed information on the dataset, download the Release Notes from here
All property docstrings have been pulled from these release notes.
Parameters:
comid (int): The comID that corresponds to the stream segment of interest.comidDict (dict): The dictionary used to map the ComIDs to the feature index in the gdb. Generally loaded into memory using json.load(filepath)src (fiona.collection): The open fiona collection representing the gdb and the 'NHDFlowline_Network' layer.warning (bool, optional): Defaults to true. Raises a warning to ensure the comidDict NHDPlus version matches that of the gdb.
Attributes / Methods:
annual_mean_flow_QA
Mean Annual Flow from runoff (cfs)
annual_mean_flow_QC
Mean Annual Flow with Reference Gage Regression applied to QB (cfs). Best EROM estimate of "natural" mean flow.
annual_mean_flow_QE
Mean Annual Flow from gage adjustment (cfs). Best EROM estimate of actual mean flow.
annual_mean_vel_QA
Mean Annual Velocity for QA (fps)
annual_mean_vel_QC
Mean Annual Velocity for QC (fps). Best EROM estimate of "natural" mean velocity.
annual_mean_vel_QE
Mean Annual Velocity from gage adjustment (fps). Best EROM estimate of actual mean velocity.
attrs
An OrderedDict of all attributes for the stream segment
comid
Common identifier of the NHD feature
comidDict
Dictionary containing the ComID -> feature index map
crs_proj4
The crs of the dataset as a proj4 string
crs_wkt
The crs of the dataset as wkt
current_month_QV
'QA': 'Mean Annual Flow from runoff (cfs)',
'VA': 'Mean Annual Velocity for QA (fps)',
'QC': 'Mean Annual Flow with Reference Gage Regression applied to QB (cfs).
Best EROM estimate of "natural" mean flow.',
'VC': 'Mean Annual Velocity for QC (fps). Best EROM estimate of "natural" mean velocity.',
'QE': 'Mean Annual Flow from gage adjustment (cfs). Best EROM estimate of actual mean flow.',
'VE': 'Mean Annual Velocity from gage adjustment (fps). Best EROM estimate of actual mean velocity.
feat_currency_date
Feature Currency Date
from_node_id
Unique identifier for the point at the top of the NHDFlowline feature
geometry
Shapely representation of the line segment
GNIS_id
Geographic Names Information System ID for the value in GNIS_Name
GNIS_name
Feature Name from the Geographic Names Information System
length_km
Feature length in kilometers
max_elev_raw
Maximum elevation (unsmoothed) in centimeters
max_elev_smoothed
Maximum elevation (smoothed) in centimeters
min_elev_raw
Minimum elevation (unsmoothed) in centimeters
min_elev_smoothed
Minimum elevation (smoothed) in centimeters
QV_meta
Metadata describing the results of current_month_QV
reach_code
Reach Code assigned to feature
resolution
NHD database resolution (i.e. 'high', 'medium' or 'local')
src
The opened fiona collection of the gdb and the 'NHDFlowline_Network' layer
stream_order
Modified Strahler Stream Order
tidal
Is Flowline Tidal? 1=yes, 0=no
to_node_id
Unique identifier for the point at the end of the NHDFlowline feature
tot_drainage_area_sqkm
Total upstream catchment area from downstream end of flowline.
WB_area_comid
ComID of the NHD polygonal water feature through which a NHD "Artificial Path" flowline flows