[GRASS-user] Re: grass-user Digest, Vol 24, Issue 9: Problems with NVIZ Volume

["Peter Löwe"]

Suenia:

I would assume that the setting of elevation of the location causes the trouble.

Maybe this will help you to set up the loaction properly:

Have a look at the code of r.in.srtm
(http://grass.itc.it/grass63/manuals/html63_user/r.in.srtm.html)
and/or consult the article by Markus Neteler about it in GRASS NEWS, VOl 3:
http://grass.itc.it/newsletter/GRASSNews_vol3.pdf

Cheers,
Peter

> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 8 Apr 2008 11:09:04 +0200 (CEST)
> From: suenia <sueniii at yahoo.de>
> Subject: [GRASS-user] Problems with NVIZ Volume (3dGRID) Visualization
> 	!
> To: grass-user at lists.osgeo.org
> Message-ID: <419470.5003.qm at web23212.mail.ird.yahoo.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
>                 Hello together !
>   I have problems with NVIZ Volume visualization !
>  Here I made an example generating a simple 3dgrid volume assuming
> subterranean data and the failing of visualizing it. I would really appreciate
> some help !  
>       Here the short workflow:
> #Generating three surfaces which will model the volume.
> GRASS 6.2.2 (4326):~ > r.mapcalc dem.t=0
> GRASS 6.2.2 (4326):~ > r.mapcalc dem.m=-10
> GRASS 6.2.2 (4326):~ > r.mapcalc dem.b=-20
>                           #My region settings
> GRASS 6.2.2 (4326):~ > g.region -p3
> projection: 3 (Latitude-Longitude)
> zone:       0
> datum:      wgs84
> ellipsoid:  a=6378137 es=0.006694379990141316
> north:      24:56:24N
> south:      12:54S
> west:       75:52:12E
> east:       114:17:24E
> top:        0.00000000
> bottom:     -20.00000000
> nsres:      0:59:44.842105
> nsres3:     0:59:44.842105
> ewres:      1:00:39.789474
> ewres3:     1:00:39.789474
> tbres:      1
> rows:       38
> rows3:      38
> cols:       38
> cols3:      38
> depths:     20
> cells:      1444
> 3dcells:    28880
> 
>  
>   #Generating the 3d grid volume
> GRASS 6.2.2 (4326):~ > r.to.rast3 input=dem.b,dem.m,dem.t output=dem –o  
>     #Visualizing it!
> GRASS 6.2.2 (4326):~ > nviz volume=dem elevation=dem.t
>  
>  When visualizing the 3dgrid volume dem, together with the raster
> surfaces, only outlines in form of a cube volume are drawn whenever navigating in
> space !!! else nothing is seen but the raster surfaces.  
>   When adding a new constant value, for example -10, to the raster volume,
> an associated unique colored surface at the bottom of the cube is
> observable.
>   So, I´m not sure about what could be the problem or my mistake in the
> settings selection.
>   Furthermore I would like to know how to change g.region res3,
> respectivly tbres for latitude longitude locations, when I try to change
> res3<0:59:44.842105 or tbres my region get's destroyed, definitely.
> For what stands the default value 1 of tbres ? 
>   
>  Could somebody offer more information about vertical resolution
> specifications for latitude longitude locations.
>       That works : Slovakia3d can be visualised by adding new constant
> value for the raster volume. 
> 
> Many thanks !
> Suena
>  
>      
-- 
Dr. Peter Löwe
<peter.loewe at gmx.de>





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