[GRASSLIST:4394] local / global depression

GRASS GRASS user
1

Hi,
I'm searching how to find directly the global (one and only one)
minimum coordinates of a raster map.
I can do that with r.fill.dir, and then display the map and
find the coordinates of local minimum with the mouse
and with d.what.rast.
But, 1) iIm not sure to get THE minimum of the map, 2) I would like
to do it with a command (or a set of command).
If anyone has a solution, I would enjoy to use it.
Thank's in advance.

--
Francois DELCLAUX ------------------------------------------------------------
UMR HydroSciences Montpellier
Universite Montpellier II - Place Eugene Bataillon
Case courrier MSE
34095 Montpellier Cedex 5 FRANCE http://www.hydrosciences.org/ mailto: delclaux@msem.univ-montp2.fr
Tel : (33) (0)4 67 14 90 11 Fax : (33) (0)4 67 14 47 74
------------------------------------------------------------

2

I'm searching how to find directly the global (one and only one)
minimum coordinates of a raster map.
I can do that with r.fill.dir, and then display the map and
find the coordinates of local minimum with the mouse
and with d.what.rast.
But, 1) iIm not sure to get THE minimum of the map, 2) I would like
to do it with a command (or a set of command).
If anyone has a solution, I would enjoy to use it.

One way to do it:

#get minimum from 'r.info -r':
MINIMUM=`r.info -r $MAPNAME | grep min | cut -f2 -d=`

# create a coverage map (integer based, fp may need slight change)
r.mapcalc 'min_cells=if($MAPNAME == $MINIMUM, 1, null() )'

note the minimum value may occur at more than one place.

r.to.sites (5.0/5.3) or r.to.vect (5.7)

s.out.ascii (5.0/5.3) or v.out.ascii (5.7)

Hamish