Hello lists!
I am writing a module that calculates the Strahler Order for all lines of a given dendritic network.
The program works on input data that meets some requirements:
The input vector map must be free of cycles. More than one tree in the input data is allowed. No given flow direction is needed. To find the outlet of each tree, a DEM must be given.
Strahler Order is not attached as a new layer yet, it is merely written to an ASCII file.
Everyone interested in this functionality can get the sources along with sparse documentation from
http://geo4.uibk.ac.at/tilde/kindl/grass/v.strahler.tgz
Copy the file to the "vector" directory of your grass source tree and unpack it with
`tar xzvf v.strahler.tgz`
`cd v.strahler` and type `make` to compile.
It should compile cleanly against current grass 6.1-cvs
If you like, you can help me developing the program:
Users:
Apply the module on a dataset of yours. Does it hang? Does it produce incorrect output? How can the behaviour of the program be improved? How should it format its output, what other options would you like to see? Can input data be treated (v.clean ..?) to make v.strahler work better? If it works, is it acceptable, performance-wise?
You can use g.gisenv set="DEBUG=4" to see more (maybe too much) information about the process.
Developers:
Are there any fundamental flaws in the design of the algorithm? Any severe quirks in the code?
Is there any solution on the treatment of cyclic graphs? How would you realize the output?
How can the code be optimized? - This is my first try in C programming, I'm sure there's a lot that can be improved.
I am looking forward to your opinions and experience, may this alpha one day become a beta!
However, I will be out-of-office for some weeks from Tuesday 8th - so this public alpha phase will last until mid-september at least.
\Flo.
Florian Kindl
Dept. of Geography
University of Innsbruck, Austria