On Sun, Mar 1, 2015 at 8:15 PM, Helmut Kudrnovsky wrote:
> Hi,
>
> in the book "Geomorphometry - Concepts, Software, Applications" I've found a
> short paragraph about the Stream power Index (SPI).
>
> the SPI can be used to describe potential flow erosion related to landscape
> processes.
>
>
> i
>> in the book SPI is defined as:
>>
>> SPI = A x tan(beta)
>>
>> where A is the specific catchment area and beta is the local slope angle.
>>
>>in link [1] there is the SAGA GIS formula.
>>
>>
>> sometimes SPI is also defined as:
>>
>> SPI = ln(A x tan(beta))
>
>This is also known as Topog
Hey Helli,
On Wed, Mar 4, 2015 at 9:46 AM, Helmut Kudrnovsky wrote:
> >> in the book SPI is defined as:
> >>
> >> SPI = A x tan(beta)
>
what about calculating A with r.watershed (flow accum) and tan(beta) with
r.slope.aspect (slope) and then using r.mapcalc to multiply them?
cheers,
madi
On Wed, Mar 4, 2015 at 9:46 AM, Helmut Kudrnovsky wrote:
>>> in the book SPI is defined as:
>>>
>>> SPI = A x tan(beta)
>>>
>>> where A is the specific catchment area and beta is the local slope angle.
>>>
>>>in link [1] there is the SAGA GIS formula.
>>>
>>>
>>> sometimes SPI is also defined
thanks for the hints for calculations.
>Since a and tan(b) are already calculated by r.watershed for TCI,
>implementing SPI (as yet another option to r.watershed) would be
>relatively easy.
it would be a quite nice addition to r.watershed. thanks.
-
best regards
Helmut
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Just recalling the v.net techniques I used on a mining project a year ago where
we had to optimize the infrastructure build and operational logistics for over
2000 drill sites, feeding several downstream processing plants.
V.net.distance in reverse will do what you need if each trip is being mad
Hi Mark,
Thanks for your tips. The use of a regular lattice is very interesting. But
I won't need anything that fancy so v.net.iso will most likely fill my
needs. I'm particularly interested in what you said about capacity
limitations and transport costs. How would you go about modeling that?
Chan
Hi Markus,
Thanks, g.gui.mapswipe seems very nice. I just haven't been able to use it
because it's not loading my data. I'm trying to use it for comparing vector
networks (31 thousand lines). I can load the left layer but when I try to
load the right layer, the dialogs just won't respond.
Does g.
Hi Daniel
The modeling approach I took used a combination of grass and postgis.
I ran v.net.iso for every processing plant - or possible processing plant - and
every farm centroid.
At this point, I did not worry about capacity limitations of the plants - you
can assume each is unconstrained.
Hi list,
We have a strds on a daily basis and we want to list all the maps in that
series from a particular date to another, i.e: all the maps belonging to
summer (from december 21st to march 20th) for all years and so on for the
rest of the seasons.
Is it possible to do that with the "where" par
Problem solved! It just needed one more try! :)
for y in 2003 2004 2005 2006 ; do
t.rast.list -s input=cla where="start_time >= '"${y}"-03-21' and start_time
<= '"${y}"-06-21'"
done
Cheers,
Vero
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On Wed, Mar 4, 2015 at 6:22 AM, Daniel Victoria
wrote:
> Hi Markus,
>
> Thanks, g.gui.mapswipe seems very nice. I just haven't been able to use it
> because it's not loading my data. I'm trying to use it for comparing vector
> networks (31 thousand lines). I can load the left layer but when I try
We use stream power in our landscape evolution script r.landscape.evol. One
version is already in the GRASS addons repository. We are continuing to enhance
and refine this.
Michael
__
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Ant
Thanks for the direction!
I have successfully worked through the examples on
http://grass.osgeo.org/grass70/manuals/libpython/script_intro.html except
for the last one about adding a module interface to a script. I copied the
code into a python file named module_interface.py. After I File-> "Launc
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