[GRASS-dev] Replacement of NVIZ

Michael Barton michael.barton at asu.edu
Sun Apr 22 23:48:26 EDT 2007

It's great that we can export GRASS data to be used in high-end
multi-dimensional visualization platforms like Paraview and MayVi2. I've
used Paraview a bit. I wouldn't call it easy or intuitive, but it is quite
sophisticated and powerful--though not particularly fast in my experience.

However, using any of these packages is not a replacement for NVIZ. NVIZ
will let a user quickly and seamlessly render 2, 2.5, 3, and 4 dimensional
data within a GRASS GIS session. This is a real bonus. And NVIZ does this
better than any other rendering engine within a GIS that I've seen. In this
sense, NVIZ has a different goal from Paraview and other dedicated
multidemensional rendering packages.

So I hope that we can get NVIZ ported to wxPython and make it an even more
seamless part of the geospatial visualization tools for GRASS. Making
tighter connections between GRASS and other, external visualization tools is
also a worthy plan--similar to the integration between GRASS and R. But
IMHO, we should not abandon NVIZ or something like it.


On 4/22/07 4:31 PM, "Sören Gebbert" <soerengebbert at gmx.de> wrote:

> Syd,
> Syd Visser schrieb:
>> Soren
>> Paraview3 uses Qt and MayaVi2 uses Wxpython thus we are leaning more
>> towards MayaVi2  although we use Paraview2.6 extensively but strictly as
>> a viewer.
>> We find MayaVi2 is also more open to user development thus easier to
>> extend.
> I'm developing with VTK and Qt since several years and have used ParaView1-2
> for several years.
> My experience with MayaVi is little, because the user interface was too
> horrible.
> IMHO ParaView3 is the better choice. It has a sophisticated but very
> intuitive user interface and is developed by well known institutes and
> kitware.
> And they are doing a great job. ParaView is designed to visualize huge
> datasets in parallel.
> MayaVi2 depends on Traits, TVTK, Envisage and wxPython. A lot of new
> dependencies (except wxPython).
> And for now i'm not able to get even the new grass wxPython gui to run on my
> debian etch system
> because of the dependencies.
> ParaView3 depends only on Qt4.2. Qt is available for many, many platforms as
> well as VTK.
> (i still don't understand why wxWidgets and python was choosen for the new
> grass gui and not Qt
> and python ...)
> The only thing we need to provide is a data server and gui plugin for
> ParaView3:
> http://www.paraview.org/Wiki/Plugin_HowTo
> And when ParaView3 reaches a stable state and i have some spare time i'm
> absolutely willingly to implement them!
> IMHO the data server and the reader/writer to the grass database
> (grass data should be modified with Paraview3 and stored back into the grass
> database :) if possible)
> should be implemented in C++ for performance reasons. I would not use the
> grass python wrapper
> to get the data into a visualization system. The grass raster, voxel and
> vector functions can be
> accessed from C++ code directly.
> The data server should provide access to the grass database to read and write
> raster, volume and vector data.
> And ParaView3 should be extended with a nice little Qt gui to access the grass
> data directly from the toolbar
> (like Qgis). We don't need to touch the ParaView3 sources, we only need to
> implement plugins.
> A screenshot of ParaView3 handling grass raster, volume and vector data
> (exported with the *.out.vtk modules)
> is available here:
> http://www-pool.math.tu-berlin.de/~soeren/grass/modules/screenshots/ParaView3_
> Screenshot_grass_data.png
> Just my two cents ...
> sorry for my English
> Best regards
> Soeren
>> Thanks
>> Syd
>> Sören Gebbert wrote:
>>> Hi,
>>> Syd Visser schrieb:
>>>> We use enthought open source tool suite http://www.enthought.com/
>>>> which contains Numpy, SciPi and numerous other packages.
>>>> our main use is with Matplotlib and Chaco for 2D graphs and MayaVi2
>>>> for 3D graphics
>>>> I think these packages would be well worth having a close look at
>>>> especially MayaVi2 (Python wrapped VTK) for the 3D graphics.
>>> I would like to prefer a C++ grass data server + grass gui plugin for
>>> paraview3
>>> to visualize 3d data. This would a nice and fast solution.
>>> Best regards
>>> Soeren
>>>> thanks
>>>> Syd

Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

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