[GRASS-user] Terrain Modeling on Small Areas

[M S]

There are a lot of great hydro tools in GRASS.  I would recommend at a
minimum, some of these below.

On Wed, Jan 28, 2009 at 2:08 PM, Frank Aragona <frank at agroinnovations.com>wrote:

> What I'd really like to know, actually, is how to do terrain modelling and
> waterflow analysis on a small area. I have a .csv file with xyz coordinates.
>  My approach has been:
>
> 1.  Import this using v.in.ascii -z input=C:some_file.csv output=vector_xyz
> format=point fs=, skip=0 x=2 y=3 z=5 cat=1
>

Try using r.in.xyz
http://grass.itc.it/grass62/manuals/html62_user/r.in.xyz.html to process the
data, look at voids, use statistics to determine an appropriate cell size,
etc.


>
> 2.  Create an interpolated raster surface with v.surf.idw from the imported
> vector map.
>

try too http://grass.ibiblio.org/gdp/html_grass63/v.surf.rst.html


> 3.  R.contour for a contour map from the output of v.surf.idw
>
> 4.  R.flow to determine flow lines of water on the map surface
>

  5.  r.terraflow for flow accumulation and dispersion
  6  r.watershed and it's outputs.

How good is your input data?  Meaning what is rough horizontal spacing?


Have Fun.
Mark


> Do you all think this is a good approach?  My area is very small, about 10
> acres.  I'm not quite sure about the quality of my outputs.  If somebody is
> willing to give some tips here, would much appreciate it.
>
> Frank Aragona
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