split_study_reach.RdProjects the click into the inherited Stream processing CRS, snaps to the selected Reach, splits its line pieces and regenerates both buffered extents with the inherited width and parent clipping. Source COMIDs remain separate from local piece identities. Previous revisions and evidence survive.
preview_study_reach_split(dsn, reach_id, point, keep_side = "downstream",
snap_distance = 200)
split_study_reach(dsn, output_file, reach_id, point, new_reach_name,
keep_side = "downstream", snap_distance = 200, report_purpose = "definition")Existing study context GeoPackage.
New context GeoPackage beside dsn. Never overwritten.
Exact saved Reach identity.
One CRS-defined sf/sfc POINT, normally a WGS84 map click.
downstream or upstream; portion retaining the original identity and name.
Maximum click-to-line distance in metres, default 200, at most 2000.
Nonempty new name, unique in the parent Stream.
definition, terrain or staging.
Requires one unbranched connected directed chain. Rejects whole-Reach endpoints, distant clicks, self-crossings, unresolved evidence and dependencies requiring reconciliation (Survey Events on the target, linked network/terrain manifest). No child records are arbitrarily reassigned. A 1 cm endpoint snap threshold prevents numerical remnants; this is not a minimum scientific Reach length. Source-relative intervals refer to the exact retained metric source line, not stationing or a different edition of NHDPlus. Cut and parent-line evidence preserve lineage through repeated edits. Evidence-first publication can leave orphan evidence after failure. No file or earlier revision is overwritten.
Preview: source, pieces, areas, cut, lengths_m, reach_id, new_reach_id, stream_id, reach_name, keep_side and snap_distance_m. Preview IDs are provisional; save recomputes and returns context/report paths, evidence, retained/new IDs.