Re: [GRASS-user] Stream power Index calculation?

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

Re: [GRASS-user] Stream power Index calculation?

>> 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

Re: [GRASS-user] Stream power Index calculation?

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

Re: [GRASS-user] Stream power Index calculation?

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

Re: [GRASS-user] Stream power Index calculation?

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 -- View this messag

Re: [GRASS-user] v.net tools with polygons

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

Re: [GRASS-user] v.net tools with polygons

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

Re: [GRASS-user] Syncronizing two displays

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.

Re: [GRASS-user] v.net tools with polygons

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.

[GRASS-user] t.rast.list and sql use

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

[GRASS-user] [solved] t.rast.list and sql use

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 ___ grass-user mailing list grass-user@lists.osgeo.org htt

Re: [GRASS-user] Syncronizing two displays

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

Re: [GRASS-user] Stream power Index calculation?

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

Re: [GRASS-user] grass-user Digest, Vol 107, Issue 2

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