[GRASS-dev] vtkGRASSBridge update

Great stuff indeed, Soeren!

Curiosity: how much faster is this compared to v.delaunay or likewise?

To me, it's not so much the speed that matters but functionality.
VTK's 2D Delaunay has a very useful "alpha" threshold setting to constrain
the triangle (by maximum triangle size).
In addition, it's capable of fitting a plane of reference through the data
points and does not assume that they lie perfectly in the X-Y plane.
This gives much better results for point clouds that describe e.g. micro relief
on a slope.

You can try this already, even without the VTK bridge: just export some
3D points to VTK, load into ParaView (3.6) and choose Delaunay 2D from
the "Filter" menu.

Now, if only we had a simple way of getting VTK data back into GRASS...

Ben

Markus
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Benjamin Ducke
Senior Applications Support and Development Officer

Oxford Archaeological Unit Limited
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@oxfordarch.co.uk

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Hello Ben,

2009/9/26 Benjamin Ducke <benjamin.ducke@oxfordarch.co.uk>:

Great stuff indeed, Soeren!

Thanks a lot. I hope this code will help to do something useful in the future.

Curiosity: how much faster is this compared to v.delaunay or likewise?

To me, it's not so much the speed that matters but functionality.
VTK's 2D Delaunay has a very useful "alpha" threshold setting to constrain
the triangle (by maximum triangle size).
In addition, it's capable of fitting a plane of reference through the data
points and does not assume that they lie perfectly in the X-Y plane.
This gives much better results for point clouds that describe e.g. micro relief
on a slope.

You can try this already, even without the VTK bridge: just export some
3D points to VTK, load into ParaView (3.6) and choose Delaunay 2D from
the "Filter" menu.

Now, if only we had a simple way of getting VTK data back into GRASS...

This is work in progress .... there will be of course a
vtkGRASSVectorPolyDataWriter()
in ... some ... weeks. :slight_smile:

Best regards
Soeren

Ben

Markus
_______________________________________________
grass-dev mailing list
grass-dev@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-dev

--
Benjamin Ducke
Senior Applications Support and Development Officer

Oxford Archaeological Unit Limited
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@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.

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