[GRASS-user] how to calculate areas

[Vincent Bain]

to my mind, one has to be cautious with this module, and be aware of how
surfaces are estimated. It appears that results show a big variability
given the current region resolution.
(just try r.surf.area on a sloppy plane [generated with r.plane],
knowing its inclination and thus its actual surface in advance)

Bye,
Vincent


Le mardi 16 septembre 2008 à 02:28 -0700, Alex Mandel a écrit :
> Alex Mandel wrote:
> > Maciej Tomaszczyk wrote:
> >> hello
> >> I have DEM of some part of mountains chain and i would like to calculate a real area of this (area in 3d not plane area).
> >> I wonder if Grass can do it.
> >> best
> >> maciej
> >>
> >> Maciej Tomaszczyk
> >> Polish Geological Institute
> >> Geological Mapping Department
> >> http://www.pgi.gov.pl
> >> http://www.opengeology.pl
> >>
> >>
> >>
> > 
> > Just to clarify, you mean surface area as opposed to footprint of the
> > mountain range. So the sum of all the surfaces of the 3d model?
> > 
> > Alex
> > 
> > 
> 
> The solution to that problem would be r.surf.area which should give you
> both the 2D and 3D area.
> You'll have to actually try this as I just read about it in Markus and
> Helena's book.
> 
> Alex
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