stream order

Stefan Jaeger stefan at
Mon May 1 08:00:00 EDT 1995

In article <{BCT-PGOTFE}> you wrote:
: I am looking for a means of automating the classification of stream 
: segments by "order". An "Order 1" stream is one that has no other 
: stream flowing into it. An "Order 2" stream is one that is formed by 
: the junction of two "Order 1" streams, etc. Can anyone suggest a 
: GRASS routine that could be used to solve this problem?

Sorry for posting this to you directly but my NNTP server does not allow
posting for some reason. Straem ordering is not a trivial thing to do from a
programming point of view. There was a fortran program listed in computers &
geosceineces some years go (< 1990). the author was Li-Ping Yuan and it did
the stream ordering in exactly the way you wanted it, which is the Strahler
system. If you can't find it in your local library, I can look for the
reference if you want, or I can e-mail you the code which was sent to me by
the author. I have made some changes to the code, mainly I/O things. To my
knowledge there is no GRASS-program available doing this job, so the task
would be either to use mapcalc or write you own routine. I highly recommend
to get a copy of the paper for you will hardly be able to understand the
algorithms without it.  I hope this helps.

Stefan J. 

Stefan Jaeger             |     e-mail: stefan at
Dept. of Geography        |         or: ca4 at
University of Heidelberg  |     Tel. +49-6221-564565
INF 348                   |     Fax  +49-6221-564996
69120 Heidelberg          |
Germany                   |

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