Joins geoconnex mainstem identifiers onto a table that contains NHDPlusV2 (comid/featureid) or NHDPlusHR (nhdplusid) identifiers using a lookup table.
add_mainstems(x, join_col = NULL, join_col_type = NULL)data.frame or sf containing an identifier column joinable to NHDPlusV2 or NHDPlusHR.
character name of the identifier column in x.
Detected automatically from comid, featureid, or nhdplusid (any case)
if not provided.
character one of "nhdpv2" or "nhdphr". Detected
automatically from join_col if not provided.
x with mainstem_uri and mainstemid columns added.
Source data comes from the ref_rivers GitHub release here. The csv source data is downloaded once, converted to parquet, and cached in the user data dir indicated by hydrogeofetch_data_dir.
The NHDPlusV2 lookup csv is roughly 120 MB and the NHDPlusHR lookup roughly 50 MB, so the mainstem functions have no examples. The first call for a given type downloads and converts the table; later calls in the same session read a cached parquet file and are fast.
old_dir <- hydrogeofetch_data_dir()
hydrogeofetch_data_dir(file.path(tempdir(), "mainstems"))
add_mainstems(data.frame(comid = c(2804607, 2804621)))
hydrogeofetch_data_dir(old_dir)