[vtkusers] scalars centered on cell

[Burlen]

Hi I have an image data dataset and I need vtk to locate the scalars at the 
centers of my cells, not at the vertices of the grid. In the picture below 
the |'s & -'s represent the grid. grid intesections are where vtk is locating 
then scalars now.  the *'s are where the scalars need to be located. This 
must be very simple to accomplish, but I haven't found any examples or docs 
someone piont me in the right direction?

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| * | * |
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| * | * |
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