[GRASS-user] announcement of strahler stream order analysis

[Jarek Jasiewicz]

 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