[GRASS-user] conditional buffering with DEM

[Ahmet Temiz]

thank you all,

Actually, I coudn't find time to test it.

perhaps creating bufferr from the line then querying these buffeds on DEM

The process is for estimating effect of Flood.
Do you suggest a way?

regards

On Friday, May 1, 2015, Nikos Alexandris <nik at nikosalexandris.net
<javascript:_e(%7B%7D,'cvml','nik at nikosalexandris.net');>> wrote:

> * Moritz Lennert <mlennert at club.worldonline.be> [2015-04-23 20:58:10
> +0200]:
>
> > On 23/04/15 16:44, Ahmet Temiz wrote:
> > > thank you Nikos
> > >
> > > I meant that  creating buffers from a line, which also querying DEM
> values.
> > >
> > > DEM is in subquery position of buffer map
> >
> > You cannot do that directly, AFAIK, but using r.mapcalc you can combine
> > the two variables. Different paths are possible. Here's one (supposing a
> > buffer of 500m):
> >
> > - Create a raster map with distance to the line using r.grow.distance
> > - Use r.mapcalc in order to check for both distance and DEM value, e.g.
> >
> > NewMap = if(DEM > 100 && DEM < 200 && distance < 500, 1, null())
> >
> > This will give you a map with non-null (value 1) in those pixels that
> > are within the buffer distance and that correspond to the DEM-related
> > condition.
> >
> > Is this what you are looking for ?
> >
> > Another path would be combining r.buffer output with the DEM in
> r.mapcalc.
> >
> > Moritz
> >
> [..]
>
> Dear Ahmet,
>
> did Moritz' suggested approach match your needs?
>
> Thank you, Nikos
>


-- 
Ahmet Temiz
Jeoloji Müh.
Afet ve Acil Durum Yönetimi Başkanlığı
Bilgi İşlem  Dairesi Başkanlığı-CBS Grubu


________________________

Ahmet Temiz
Geological Eng.
Information Systems - GIS Group
Disaster and Emergency Management
of Presidency
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