This repo serves as an example of how to work with and trace the National Water Model (NWM) stream network

definitions, requirements:

features streams and lakes in the NWM

feature_ids (FIDs) are the unique identifiers for features

Dependencies: R, rgdal, rgeos (maybe?)

Input files:

• route_link.nc can be obtained from NWM DOMAIN files (a.k.a. hydrofabric)
• shapefile containing flowlines (fl); the actual network TODO: where did I get this?
• shapefile containing shoreline data BYOSL (bring your own shoreline; make sure proj matches fl)

program sequence

1. preprocess.R

   • generates the upstream network ("from") based on the downstream network ("to") provided by route_link.nc; this takes a while
   • identifies the terminal stream segments based on the intsersection of flowlines and shoreline polygon

2. terminal.R

   • illustrates how to use the output of preprocess.R
   • contains a function to iteratively trace up the network from a given stream segment or segments