[Paraview] [Xdmf] xdmf + vtk image extents

[Dominik Szczerba]

HI David,

As I see it, you have two blocks here with separate origins. It can be
used to approximate what I want, but it is not the same. I mean one
origin for all blocks, but different extents, just like outputs from
vtkExtractVOI. VTK XML formats can store such information. But I guess
this concept is too VTK specific... please correct me if I am wrong.

Thanks,
Dominik

On Fri, May 27, 2011 at 11:45 PM, David E DeMarle
<dave.demarle at kitware.com> wrote:
> I think the "Collection" Gridtype is the answer for this.
> Specify the whole object via the collection grid and the individual pieces
> as subgrids each covering different portions of the domain.
> Below is a fake example, (I couldn't get parallel paraview git master server
> to write the wavelet source out correctly, but suspect an earlier version
> would), but the overall layout should look like this:
> <?xml version="1.0" ?>
> <!DOCTYPE Xdmf SYSTEM "Xdmf.dtd" []>
> <Xdmf xmlns:xi="http://www.w3.org/2003/XInclude" Version="2.2">
>   <Domain>
>   <Grid Name="Wavelet" GridType="Collection">
>     <Grid GridType="Uniform">
>       <Topology TopologyType="3DCORECTMesh" Dimensions="11 21 21"/>
>       <Geometry GeometryType="ORIGIN_DXDYDZ">
>         <DataItem Name="Origin" Dimensions="3" NumberType="Float"
> Precision="4" Format="XML">
> 0 0 0
> </DataItem>
>         <DataItem Name="Spacing" Dimensions="3" NumberType="Float"
> Precision="4" Format="XML">
> 1 1 1
> </DataItem>
>       </Geometry>
>       <Attribute Name="RTData" Active="1" AttributeType="Scalar"
> Center="Node">
>         <DataItem Dimensions="11 21 21" NumberType="Float" Precision="4"
> Format="HDF">/Users/demarle/tmp/wavelet1.h5:/Data0</DataItem>
>       </Attribute>
>     </Grid>
>     <Grid GridType="Uniform">
>       <Topology TopologyType="3DCORECTMesh" Dimensions="10 21 21"/>
>       <Geometry GeometryType="ORIGIN_DXDYDZ">
>         <DataItem Name="Origin" Dimensions="3" NumberType="Float"
> Precision="4" Format="XML">
> 10 0 0
> </DataItem>
>         <DataItem Name="Spacing" Dimensions="3" NumberType="Float"
> Precision="4" Format="XML">
> 1 1 1
> </DataItem>
>       </Geometry>
>       <Attribute Name="RTData" Active="1" AttributeType="Scalar"
> Center="Node">
>         <DataItem Dimensions="10 21 21" NumberType="Float" Precision="4"
> Format="HDF">/Users/demarle/tmp/wavelet2.h5:/Data0</DataItem>
>       </Attribute>
>     </Grid>
>   </Grid>
>   </Domain>
> </Xdmf>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 28 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-371-3971 x109
>
>
> On Thu, May 26, 2011 at 4:48 AM, Dominik Szczerba <dominik at itis.ethz.ch>
> wrote:
>>
>> Hi,
>>
>> I have realized that Xdmf does not have a concept of "extents", just
>> as vtkImageData does.
>> This is a problem for me, because I need to store separate VOI's that
>> make up one consistent canvas.
>> What's the best way to accomplish this with Xdmf? I am aware of the
>> HyperSlab concept, but the examples I saw so far were of the type:
>>
>> <DataItem ItemType="HyperSlab"
>>  Dimensions="25 50 75 3"
>>  Type="HyperSlab">
>>  <DataItem
>>    Dimensions="3 4"
>>    Format="XML">
>>    0 0 0 0
>>    2 2 2 1
>>    25 50 75 3
>>    </DataItem>
>>    <DataItem
>>    Name="Points"
>>    Dimensions="100 200 300 3"
>>    Format="HDF">
>>    MyData.h5:/XYZ
>>  </DataItem>
>> </DataItem>
>>
>> e.g. referencing subset of some full, but existing dataset. I do not
>> have this full dataset, I have multiple ones making up for one full.
>> How do others deal with this?
>>
>> Best regards,
>> Dominik
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>
>