[GRASS-user] Lake modelling using volume interpolation (v.vol.rst and Paraview)

[Craig Wilson]

Hamish,

 

Having tried r.to.rast3, r.to.rast3elev, v.to.rast3 and v.vol.rst, I can now create a number of G3D files showing the carbon levels, however they are only in planar form. In NVIZ I load the DEM file I already created as elevation and colour, then the DIC file as the 3D raster. After some fiddling about, it appears as a 2D surface on the loch (depsite error messages popping up about working with a scalar variable), which can be lowered or raised using the Position bar, however the colours stay the same. This is the first time I've got any of the 3D Loch Lomond data to work in NVIZ, it's just a shame it's not actually represented in 3D!

 

In Paraview, I load the same files and again see a 2D surface. By increasing the z-exaggeration I can create a second surface underneath the first one, showing the same interpolated carbon values, but with nothing in between the two.

 

Re: nnbathy, I followed the link to the Grass Add-On site but found now way to download the file! In any event I have a 2.5D DEM of the Loch, but thanks anyway.

 

The other issue I'm having is the creation of a mask for the lake. I created the outline of the shore in vector point form(573 points), but have tried multiple ways to convert it into an area or polygon with no success. Even the v.type_wrapper tool, which converts points, centroids, faces, lines and areas didn't help. This is relatively simple in ArcGIS, but I still haven't found a way to creat polygons in GRASS, even through v.digit, so I'm probably missing something obvious!
 

> Date: Mon, 26 Jul 2010 23:44:27 -0700
> From: hamish_b at yahoo.com
> Subject: Re: [GRASS-user] Lake modelling using volume interpolation (v.vol.rst and Paraview)
> To: grass-user at lists.osgeo.org; craiging619 at hotmail.com
> 
> Is the temperature & carbon in e.g. continuous vertical CTD profiles
> down through the water column, random water samples from "various" mid-water
> depths, or from bottom samples, or..?
> 
> btw, what sort of "carbon" data are we talking about? DOC levels? isotopes?
> 
> 
> if from like CTD data with hi-res in the vertical but stations being
> spaced some far distance horizontally) you can also split it up into
> a series of 2D vertical sections at each depth, run v.surf.rst for each
> one, then stack all those 2D slices together with r.to.rast3 for your
> 3D raster block.


The data is in 84 water columns with 3 measurements each - the surface, a mid depth then one near the lake bed. Dissolved Inorganic Carbon and Temperature was measured at each point. 21 columns were measured in each of the 4 seasons of the year, so the idea was to build up a time comparison as well.

 

Thanks for your help,

 

Craig
 		 	   		  
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