R.stream.* modules
Modules r.stream.order r.stream.basins, r.stream.distance and r.stream.stats are prepared to perform Hortonian analysis in GRASS GIS. Modules can work with outputs data of r.watershed and r.stream.extract being preparing by Markus Metz.
The tutorial/presentation was prepared with North Carolina Dataset.
http://grass.osgeo.org/download/data.php
As a base map elev_ned_30_m was used. Regions setings for analysis:
projection: 99 (Lambert Conformal Conic)
- zone: 0
- datum: nad83
- ellipsoid: a=6378137 es=0.006694380022900787
- north: 228500
- south: 215000
- west: 630000
- east: 645000
- nsres: 30
- ewres: 30
- rows: 450
- cols: 500
- cells: 225000
Because r.stream.extract is still in progress analysis will be based on r.watershed results. Stream network has been obtained with r.watershed in MFD mode:
r.watershed -f elevation=elev threshold=700 accumulation=accum drainage=dirs stream=streams convergence=5
Be sure you set the region for analysis before run it.
g.region rast=elev_ned_30_m
For future analysis following map produced by r.watershed are requied: streams with streams network, dirs with flow direction and accum with flow accumulation.
r.stream.order
Module r.stream.strahler may order stream network according four most popular ordering systems. Module can create both all four at once or every order separete
r.stream.order stream=streams dir=dirs accum=accum strahler=strahler shreve=shreeve horton=horton hack=hack