NLDI Flowtools package
Main module.
- nldi_flowtools.nldi_flowtools.flowtrace(lon, lat, direction)
Trace the flowpath from a point to the nearest NHD flowline.
- Parameters:
lon (float) – Longitude of the input point in WGS 84 decimal degrees.
lat (float) – Latitude of the input point in WGS 84 decimal degrees.
direction (str) –
Specifies which portion of the NHD flowline to return:
”up”: Returns the upstream portion of the intersected flowline.
”down”: Returns the downstream portion of the intersected flowline.
”none”: Returns the entire intersected flowline.
- Returns:
A GeoJSON FeatureCollection containing:
NHD Flowline (geojson.Feature): The intersected NHD stream segment,
which may be full, upstream, or downstream depending on direction. - Raindrop Path (geojson.Feature): The traced path from the input point to the NHD flowline.
- Return type:
geojson.FeatureCollection
- nldi_flowtools.nldi_flowtools.splitcatchment(lon, lat, upstream)
Delineate the drainage basin from the input point.
This function identifies the local NHDP catchment containing the input coordinates and determines the upstream drainage area. It returns the local catchment and, depending on the upstream flag, either the split catchment or the full upstream drainage basin.
- Parameters:
lon (float) – Longitude coordinate of the input point in WGS 84 decimal degrees.
lat (float) – Latitude coordinate of the input point in WGS 84 decimal degrees.
upstream (bool) –
True: Returns the full upstream drainage basin.
False: Returns the portion of the drainage basin within the local catchment.
- Returns:
A GeoJSON FeatureCollection containing:
- Catchment (geojson.Feature): The NHD catchment. This is the catchment
that gets “split.”
- SplitCatchment (geojson.Feature, optional): The portion of the catchment
upstream of the input point. This is included if upstream=False.
- DrainageBasin (geojson.Feature, optional): The full upstream drainage
basin if applicable. This is included if upstream=True.
- Return type:
geojson.FeatureCollection