[GRASS-user] displaying volumes from xyz vector in nviz

ian summers i.summers at hotmail.co.uk
Thu Aug 21 07:13:52 EDT 2008

Hello Ben,
Thank you for your suggestion but when I attempt to run r,to.rast3 I get the 'position not in queue' message again.  I ran v.kernel on the respective slices with st deviation of 5 leaving all other parameters as they were.  Was this correct? Having used the v.info command the layers are 3D. Essentially what I am trying to achieve is a volume cube of loch lomond from x, y, z coordinates. 
 I also have dissolved organic carbon data which i was hoping to display volumetrically within this that has x, y, z, DOC columns.  I ran v.vol.rst but it says w column not supported. my data here is:-
My main focus is the volume cube of loch lomond. The DOC would be a bonus.
> Date: Thu, 21 Aug 2008 09:55:07 +0100> From: benjamin.ducke at oxfordarch.co.uk> CC: grass-user at lists.osgeo.org> Subject: Re: [GRASS-user] displaying volumes from xyz vector in nviz> > To generate a volumetric model of your point data, you need to use> an algorithm that can interpolate an attribute in 3D space.> > To start with, you need to make sure that your input points map is> actually a 3D geometry, not just 2D points with X,Y and Z attributes> attached (us v.info to find out).> > v.to.rast3 simply takes the 3D point positions and creates a single> voxel value at every point location in the input map. Most likely, this> is not what you want and you should look into v.vol.rst instead.> > The question then is WHAT to interpolate. In your attribute table list> below, I cannot see an attribute that could actually be used for> interpolation. The only thing you have are integer categories.> > If you want to show point density in 3D: there is currently no GRASS> module to calculate that. So the only thing you can do is calculate> density for 2D slices at different Z ranges separately (use v.select> to query out points for each Z range, then run v.kernel on them) and> stack the resulting 2D raster maps on top of each other to form a voxel> cube using r.to.rast3.> > Ben> > > ian summers wrote:> > Dear all,> > > > I have a vector point file and have tried to run the program v.to.rast3 > > though in the 'column name' section I am unsure what to enter? the > > column attributes for the data are as follows.> > > > > INTEGER/cat> > > INTEGER/Id> > > DOUBLE PRECISION/X> > > DOUBLE PRECISION/Y> > > DOUBLE PRECISION/Z> > > > I have tried entering cat, id and z in this box but in the output I > > receive the message 'position not in queue'.> > > > I have also tried to create the volume using r.to.rast3 and though it > > appears as though a file is created when it comes to display in nviz > > only a plain 2D white tile appears. The values in my Z column are > > negative as I am modelling a lake. I am unsure whether this holds any > > bearing on outcome.> > > > Hope someone can help.> > > > Ian Summers> > > > > > ------------------------------------------------------------------------> > Win £3000 to spend on whatever you want at Uni! Click here to WIN! > > <http://clk.atdmt.com/UKM/go/101719803/direct/01/>> > > > > > ------------------------------------------------------------------------> > > > _______________________________________________> > grass-user mailing list> > grass-user at lists.osgeo.org> > http://lists.osgeo.org/mailman/listinfo/grass-user> > > -- > Benjamin Ducke> Senior Applications Support and Development Officer> > Oxford Archaeology Ltd> Janus House> Osney Mead> OX2 0ES> Oxford, U.K.> > Tel: +44 (0)1865 263 800 (switchboard)> Tel: +44 (0)1865 980 758 (direct)> Fax :+44 (0)1865 793 496> benjamin.ducke at oxfordarch.co.uk> > > > > ------> Files attached to this email may be in ISO 26300 format (OASIS Open Document Format). If you have difficulty opening them, please visit http://iso26300.info for more information.> > _______________________________________________> grass-user mailing list> grass-user at lists.osgeo.org> http://lists.osgeo.org/mailman/listinfo/grass-user
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