Hi,
recently my colleagues hydrologists asked me whether it is possible to
create basins of similar area using GRASS. Let's say you have DEM
available for area of interest and want to create basis of area size
4-5 km2.
Do you have any idea? Thanks! Ma
--
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa
Use r.wathershed or r.basins.
On Thu., Apr. 25, 2019, 11:04 Martin Landa, <landa.martin@gmail.com> wrote:
Hi,
recently my colleagues hydrologists asked me whether it is possible to
create basins of similar area using GRASS. Let’s say you have DEM
available for area of interest and want to create basis of area size
4-5 km2.Do you have any idea? Thanks! Ma
–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa
grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user
Hi,
čt 25. 4. 2019 v 17:19 odesílatel Francois Chartier
<fra.chartier@gmail.com> napsal:
Use r.wathershed or r.basins.
well, I know these tools. I am just not sure how to control optimal
basin area (eg. 4-5km2). I just found `threshold` parameter.
Anyway, thanks for feedback. Ma
--
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa
Am 25. April 2019 17:29:24 MESZ schrieb Martin Landa <landa.martin@gmail.com>:
Hi,
čt 25. 4. 2019 v 17:19 odesílatel Francois Chartier
<fra.chartier@gmail.com> napsal:Use r.wathershed or r.basins.
well, I know these tools. I am just not sure how to control optimal
basin area (eg. 4-5km2). I just found `threshold` parameter.
I don't really see how a homogeneous size could actually make sense. The threshold allows you to define a minimum size, but depending on the actual topography actual sizes of basins will always differ.
Moritz
On Thu, Apr 25, 2019 at 5:34 PM Moritz Lennert <mlennert@club.worldonline.be> wrote:
Am 25. April 2019 17:29:24 MESZ schrieb Martin Landa <landa.martin@gmail.com>:
Hi,
čt 25. 4. 2019 v 17:19 odesílatel Francois Chartier
<fra.chartier@gmail.com> napsal:Use r.wathershed or r.basins.
well, I know these tools. I am just not sure how to control optimal
basin area (eg. 4-5km2). I just foundthresholdparameter.I don’t really see how a homogeneous size could actually make sense. The threshold allows you to define a minimum size, but depending on the actual topography actual sizes of basins will always differ.
I agree. A solution could be manual editing: merge basins by adhering hydrological rules (merge a downstream basin with an upstream basin granted that other upstream basins do not become isolated). But hydrologically this does not make sense, compare with stream order numbers.
Markus M
Maybe make basins with threshold an order of magnitude smaller. Then merge small areas to get your 4-5 km2 areas. Still not totally sure how this makes sense hydrologically.
-k.
Please excuse brevity. Sent from tiny pocket computer with non-haptic feedback keyboard.
On Thu, Apr 25, 2019, 16:05 Markus Metz <markus.metz.giswork@gmail.com> wrote:
On Thu, Apr 25, 2019 at 5:34 PM Moritz Lennert <mlennert@club.worldonline.be> wrote:
Am 25. April 2019 17:29:24 MESZ schrieb Martin Landa <landa.martin@gmail.com>:
Hi,
čt 25. 4. 2019 v 17:19 odesílatel Francois Chartier
<fra.chartier@gmail.com> napsal:Use r.wathershed or r.basins.
well, I know these tools. I am just not sure how to control optimal
basin area (eg. 4-5km2). I just foundthresholdparameter.I don’t really see how a homogeneous size could actually make sense. The threshold allows you to define a minimum size, but depending on the actual topography actual sizes of basins will always differ.
I agree. A solution could be manual editing: merge basins by adhering hydrological rules (merge a downstream basin with an upstream basin granted that other upstream basins do not become isolated). But hydrologically this does not make sense, compare with stream order numbers.
Markus M
grass-user mailing list
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Hi,
čt 25. 4. 2019 v 20:14 odesílatel Ken Mankoff <mankoff@gmail.com> napsal:
Maybe make basins with threshold an order of magnitude smaller. Then merge small areas to get your 4-5 km2 areas. Still not totally sure how this makes sense hydrologically.
right, it doesn't make sense probably from hydrologic point of view.
Let me explain reasoning. My colleagues are working on developing
distributed event-based model for surface and subsurface runoff and
erosion. We are working on experimental version which enables
computation parallelization. In initial phase AOI is split into tiles.
Instead of regular grid of tiles a basin-based tiles are used. This is
reason why basins (defining tiles) should be of similar area size.
Martin
--
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa
Hi,
Not to hijack this thread…but
Actually what Martin is asking for would be useful for us in geochemical mineral exploration. Having GRASS create 4-5km2 (or whatever size range) basins/catchments automatically would be useful to create tentative stream sediment sample locations. I prefer to create my stream sediment sample locations based upon catchment size much more than the traditional & often miss used stream order method.
There is my two cents.
Phil
On Fri, Apr 26, 2019 at 7:35 AM Martin Landa <landa.martin@gmail.com> wrote:
Hi,
čt 25. 4. 2019 v 20:14 odesílatel Ken Mankoff <mankoff@gmail.com> napsal:
Maybe make basins with threshold an order of magnitude smaller. Then merge small areas to get your 4-5 km2 areas. Still not totally sure how this makes sense hydrologically.
right, it doesn’t make sense probably from hydrologic point of view.
Let me explain reasoning. My colleagues are working on developing
distributed event-based model for surface and subsurface runoff and
erosion. We are working on experimental version which enables
computation parallelization. In initial phase AOI is split into tiles.
Instead of regular grid of tiles a basin-based tiles are used. This is
reason why basins (defining tiles) should be of similar area size.
Martin–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa
grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user
Hi Martin,
Margherita Di Leo