R/drainage_exploration.R
get_drainage_context.RdRetrieves WBD 2025 HUC12 polygons containing the snapped point, an NLDI catchment-based upstream basin, and distance-limited upstream tributaries and downstream mainstem. Basin geometry is simplified for exploration, is NOT split at the clicked point, and is not an exact pour-point delineation. Network completeness is not established by these distance-limited requests. These are reference candidates, not FG Study Area, Stream or Reach records. No project files are read or written. Coordinates are sent to USGS services.
get_drainage_context(location, distance_km = 50, include_names = FALSE)A result of [locate_drainage_stream()].
Navigation distance in kilometres, from 1 to 200, for each network direction. The basin and HUC12 queries do not use this distance.
Retrieve optional GNIS channel names with one attribute-only Fabric query for up to 500 distinct returned COMIDs. Defaults to FALSE.
A list with `location`, `layers` (named sf or NULL), `status` (one row per layer: layer, status, features, detail, outcome), `distance_km`, `retrieved_at`, `sources`, and `network_complete` (NA). Individual layer failures are retained as unavailable without discarding other results or asserting no coverage. `outcome` distinguishes `available`, `no_features` (an explicit empty sf response or no containing HUC), `service_unavailable` (transport evidence), and `unresolved` (including NULL with no retained transport evidence). `name_lookup` records optional name-query status and details; name-query failure never discards successfully retrieved geometry.