[GRASS-user] S.K. Jenson and J.O. Domingue (1988) method to filter the elevation map

GRASS GRASS user
1

Hello everyone,

I'd like to know if Grass still uses the S.K. Jenson and J.O. Domingue
(1988) method to filter the elevation map, in its original conception. I've
read about some new and more improved methods and was wondering if there
wasn't any improvement in Grass method.

Thank you.

--
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2

I assume you refer to:
https://grass.osgeo.org/grass78/manuals/r.fill.dir.html

There is also:
https://grass.osgeo.org/grass78/manuals/r.terraflow.html
and
https://grass.osgeo.org/grass76/manuals/addons/r.hydrodem.html
as well as a couple of AddOns based on richdem (starting with r.richdem.*):
https://github.com/OSGeo/grass-addons/tree/master/grass7/raster



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Maybe that helps. Can you inform us about the new methods you had in mind?

Cheers
Stefan

···

Fra: grass-user grass-user-bounces@lists.osgeo.org på vegne av Luis Moreira lfsmmoreira@gmail.com
Sendt: onsdag 11. desember 2019 14:16
Til: grass-user@lists.osgeo.org grass-user@lists.osgeo.org
Emne: [GRASS-user] S.K. Jenson and J.O. Domingue (1988) method to filter the elevation map

Hello everyone,

I’d like to know if Grass still uses the S.K. Jenson and J.O. Domingue
(1988) method to filter the elevation map, in its original conception. I’ve
read about some new and more improved methods and was wondering if there
wasn’t any improvement in Grass method.

Thank you.

–
Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html

grass-user mailing list
grass-user@lists.osgeo.org
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3

On Wed, Dec 11, 2019 at 2:16 PM Luis Moreira <lfsmmoreira@gmail.com> wrote:

Hello everyone,

I’d like to know if Grass still uses the S.K. Jenson and J.O. Domingue
(1988) method to filter the elevation map, in its original conception. I’ve
read about some new and more improved methods and was wondering if there

wasn’t any improvement in Grass method.

r.watershed, available in GRASS since the late 1980’s, uses an improved method that provides more realistic results, especially with regard to errors in the elevation map. As Stefan Blumentrath mentioned, there are by now other modules that use the more realistic method of r.watershed, particularly r.stream.extract and r.hydrodem.

Be aware that r.terraflow still uses the the method of Jenson and Domingue (1988).

Markus M

Thank you.

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4

"Can you inform us about the new methods you had in mind?"

Well, there is a software (IPH-Hydro Tools) [from the Large Scale Hydrology
research group of the Institute of Hydraulic Research at the Federal
University of Rio Grande do Sul, in Porto Alegre, Brazil] which gives us
three options as methods to remove depressions, namely:
Heuristic Search (HS), Priority First Search (PFS) and Modified Heuristic
Search (MHS).
Do you know if GRASS uses one of theses methods?

As for my previous question:
I read in Grass manual:
"r.fill.dir filters and generates a depressionless elevation map and a flow
direction map from a given raster elevation map. The method adopted to
filter the elevation map and rectify it is based on the paper titled
"Extracting topographic structure from digital elevation model data for
geographic information system analysis" by S.K. Jenson and J.O. Domingue
(1988)."
I just want to know if indeed r.fill.dir function still operates precisely
in the same methodology described in the mentioned paper. I am asking
specifically about r.fill.dir, no r.watershed or other funcion.

Thank you in advance!

--
Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html

5

On Thu, Dec 12, 2019 at 2:40 PM Luis Moreira <lfsmmoreira@gmail.com> wrote:

“Can you inform us about the new methods you had in mind?”

Well, there is a software (IPH-Hydro Tools) [from the Large Scale Hydrology
research group of the Institute of Hydraulic Research at the Federal
University of Rio Grande do Sul, in Porto Alegre, Brazil] which gives us
three options as methods to remove depressions, namely:
Heuristic Search (HS), Priority First Search (PFS) and Modified Heuristic
Search (MHS).
Do you know if GRASS uses one of theses methods?

I can’t tell yet, but the search methods of the IPH-Hydro Tools could be similar to what r.watershed/r.stream.extract/r.hydrodem use.

As for my previous question:
I read in Grass manual:
“r.fill.dir filters and generates a depressionless elevation map and a flow
direction map from a given raster elevation map. The method adopted to
filter the elevation map and rectify it is based on the paper titled
“Extracting topographic structure from digital elevation model data for
geographic information system analysis” by S.K. Jenson and J.O. Domingue
(1988).”
I just want to know if indeed r.fill.dir function still operates precisely
in the same methodology described in the mentioned paper. I am asking
specifically about r.fill.dir, no r.watershed or other funcion.

The manual of r.fill.dir is correct.

Markus M