[vtkusers] vtkContourGrid ???
jbiddiscombe at skippingmouse.co.uk
Thu Mar 22 13:09:25 EST 2001
I use a similar trick which is to triangulate the random data points to get
a surface. Then Fire rays at the surface along a regular grid and end up
with a structuredpoints dataset. This can then be contoured. (it's not as
much work as you'd think). The surface is not analytical, but can be used
as a first stab.
I have made a "vtkSurfaceProbeFilter" for doing exactly this, but it's not
available (at the time of writing) for general use - apologies.
>If your data points are random, you can use a gridding algorithm to convert
>them to a structured points data set (not part of VTK). A simple inverse
>distance weighted algorithm works well but there are better methods. Then
>its easy enough to contour the data set and display it as shown in the gif
>you provided or as contour lines. The image can then be written out as a
>BMP, TIFF or CGM.
>We do this all the time for our clients in the oil business. If you would
>like more help on the gridding, let me know.
>One thing about being impatient, in the consulting world, it drives up the
>The Scotia Group, Inc.
>At 11:14 AM 3/22/01 -0600, you wrote:
> >I have searched the web, and the email archive for hints on how to use
> >vtkContourGrid, but can't seem to figure it out.
> >My problem is this: I want to draw a contour plot of antenna signal
> >strengths. I have a bunch of X & Y positions, and signal strengths. I want
> >to draw a 2D contour plot of them in a 2D window. Something like this:
> >Since my input is not in a regular grid, I know that I first have to fit
> >some kind of curve to it to get a regular grid first, and then I can draw
> >the contour plot. I believe that vtkContourGrid is what I need, but can't
> >figure out how to make use of it.
> >I also want a normal 2D plot, not a 2D overlay in an OpenGL window, but a
> >real 2D plot if possible.
> >I've already ordered both books, but I don't want to wait until next week to
> >get this problem solved - I'm impatient :-)
> >Are there any kind soles out there willing to help me with this problem?
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