Re: Problems with resampling

Hi Gunnar,

A very hard problem to diagnose based on the two JPEGs.
I can think of four possibilities:

1. There is a bug in Irregular3Det.valueToInterp(), in which
case we need a lot more information to reproduce it.

2. The difference between our resample methods is in how
we handle points that fall on the outside boundary of the
convex hull of the irregular points.

3. If you have any missing values, how our resample
methods differ in handing that.

4. Perhaps the topology you are passing to DelaunayCustom
does not include all the tetrahedra that you are using in
your resample method.

Cheers,
Bill
----------------------------------------------------------
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
http://www.ssec.wisc.edu/~billh/vis.html


On Wed, 17 Apr 2002, Gunnar Sletta wrote:

>
> Hello
>
> I've been having some problems with resampling datasets based on the 
> Irregular3DSet class. I've created the irregular set from a DelaunayCustom 
> object which received the tri and elm array as input. The other arrays were 
> left to the delaunay object to complete. The irregular data was resampled on 
> a Linear3DSet of size 64x64x64 using weighted average and no error. The 
> result can be seen in image 
> http://www.ifi.uio.no/~gunnarsl/stuff/resample.jpg. It looks a bit sparse.
>
> The image http://www.ifi.uio.no/~gunnarsl/stuff/myresample.jpg is the result 
> of the same irregular dataset but I used my irregular set resample method, 
> which uses the tri and elm arrays from the delaunay to resample the field 
> values directly. The volume is dense.
>
> Also, if I use the IsoContour display map, the field from VisAD's resample() 
> method has a lot of holes, while the field from my own method is smooth.
>
> Has you experienced anything like this, or any clue as to what might be 
> causing it?
>
> Thanks
>
> Gunnar
>
>
>
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