[GRASS-user] Raster processing

Hi

I am a new user of GRASS

I have been working on a python Geo-processing tool in ESRI ARCGIS desktop. This is basically a DEM data processing which involves “Extract by Mask” “Flow Direction”, “Flow Accumulation”,“Slope” ,“Watershed” ,"Zonal statistics "

I would like to rewrite the tool to make it work with GRASS so that later everyone can use this. I have gone through the documentation but I really not able to figure out the equivalent commands in Grass.

Could some one can give me some idea about the equivalent commands.

Thank you

sur

On Mon, 28 Jan 2013, Surendran Neelakantan wrote:

I have been working on a python Geo-processing tool in ESRI ARCGIS
desktop. This is basically a DEM data processing which involves "Extract
by Mask" "Flow Direction", "Flow Accumulation","Slope" ,"Watershed"
,"Zonal statistics "

   Take a look at the Wiki for hydrological modeling. All these capabilities
are already built in.

Rich

On Mon, Jan 28, 2013 at 7:33 PM, Surendran Neelakantan
<surendrankn@gmail.com> wrote:

Hi

I am a new user of GRASS

I have been working on a python Geo-processing tool in ESRI ARCGIS desktop.
This is basically a DEM data processing which involves "Extract by Mask"
"Flow Direction", "Flow Accumulation","Slope" ,"Watershed" ,"Zonal
statistics "

I would like to rewrite the tool to make it work with GRASS so that
later everyone can use this. I have gone through the documentation but I
really not able to figure out the equivalent commands in Grass.

First of all, set the region to the DEM with

g.region -p rast=DEM

Create a MASK with r.mask or r.mapcalc or r.to.vect

Zoom to the masked area

g.region -p zoom=DEM

Note that there is no need to clip or extract a subregion of the DEM
if the region is set properly

Flow direction, flow accumulation, watershed can be calculated with r.watershed

Slope can be calculated with r.slope.aspect

Zonal statistics can be calculated with r.univar or r.statistics or
r.statistics2 or r.statistics3, depending on the desired output.

HTH,

Markus M

Hi,

Maybe this links can be useful for you:

http://grasswiki.osgeo.org/wiki/Creating_watersheds

http://www.surfaces.co.il/?p=241

http://www.ing.unitn.it/~grass/docs/tutorial_62_en/htdocs/esercitazione/dtm/dtm4.html

http://profmarcello.blogspot.com.br/2012/12/grass-gis-calculo-do-comprimento-do-rio.html

Regards,

Marcello Benigno B. de Barros Filho
Prof. do Curso Superior de Tecnologia em Geoprocessamento - IFPB
Mestre em Ciências Geodésicas e Tecnologias da Geoinformação - UFPE
Doutorando em Tecnologia Ambiental e Recursos Hídricos - UFPE
http://profmarcello.blogspot.com
http://about.me/marcello.benigno

2013/1/29 Marcello Benigno <benigno.marcello@gmail.com>:

http://www.ing.unitn.it/~grass/docs/tutorial_62_en/htdocs/esercitazione/dtm/dtm4.html

Note also the updated version:
http://www.ing.unitn.it/~grass/docs/tutorial_64_en/htdocs/esercitazione/dtm/dtm4.html

Markus