Hi list!
I just finish first version of new grass module r.stream. Module is
regular Grass module, written in C an has no addational dependencies. It
was compiled with GRASS65 devel downloaded in last two week. Source
code you can find here:
http://heretic.livenet.pl/heretic/r.stream.tar.gz
Module compiles and seems to work. Analysis was tested only on one dataset.
To compile it copy r.streams directory to your grassXX../raster/ cd
r.stream run make and make install
What module calculate:
- strahler stream order
- shreeve stream magnitude
- class of topological elements of drainage networks
Module use r.watershed outputs: SDF flow direction and SDF stream network.
Analysis of r.stream shall be run on same regions setings as
r.watershed. If no, run g.region rast=your_dir_file first. For now
module do not check if region and rasters are identical. It is planned
to add in nearest feature. It also do not check if dirs and streams are
SDF result. Threre are no addational description. It will be added after
testing.
It works only on cells data. Floating points data are not allowed (and
have no sense).
Module is quite fast. 3000 x3000 cells all three analysis runs no more
than 30 s. on AMD 3800 2GB, Ubuntu 8.04
Module is part of comprehensive project which will add full Horton
analysis and some addational terrrains analysis to Grass. More details
in the feature. Any cooperation is welcome. The next module I plan is
directional vectorisation of stream network.
For now module is available only form web address pointed below. After
testing and removing critical errors it will be added to grass add-ons
(or maybe to main branch?).
Any coments, improvements and critics is very welcome.
More advanced Grass developers: Please check my code. Its funny, but I
don't know C.
General code is based on GRASS r.topindex module (by Keith Beven and
Huidae Cho, strongly modified)
Strahler stream order algorithm from Saga GIS (by Victor Olaya, modified)
Shreeve stream magnitude and class of topological network are my own ideas
Test and enjoy.
Jarek Jasiewicz
Adam Mickiewicz University, Poznan
Geoecology and Geoinformation Institute
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