[vtkusers] vtkImageAccumulate

[Ula Popov]

Hi Liam,

this is how I usually add arrays to image data

        vtkDataArray *Velocity;
        Velocity = Velocity->CreateDataArray(VTK_DOUBLE);
        Velocity->SetNumberOfComponents(3);
        Velocity->SetNumberOfTuples(grid->GetNumberOfPoints());
        Velocity->SetName("vertexVelocity");
        grid->GetPointData()->AddArray(Velocity);

        vtkDataArray *Density;
        Density =Density ->CreateDataArray(VTK_DOUBLE);
        Density->SetNumberOfComponents(1);
        Density ->SetNumberOfTuples(grid->GetNumberOfPoints());
        Density->SetName("Density");
        grid->GetPointData()->AddArray(Density);

I checked my arrays, they look ok.
I was able to calculate avg just using for-loop,
but I'd still like to understand/use vtk functions for
these tasks.

Thank you,
ula



On Fri, Apr 29, 2011 at 3:07 AM, Liam Kurmos <quantum.leaf at gmail.com> wrote:

> hi Ula,
>
> can i see the code for how you add the 2 fields to the imagedata?
>
> thanks,
>
> Liam
>
>
> On Fri, Apr 29, 2011 at 7:33 AM, Ula Popov <ula.popov at gmail.com> wrote:
> > Hello all,
> >
> > I have an object of class vtkImageData.
> > It has two arrays: density (scalar) and velocity (vector).
> >
> > I want to know mean and median values of the density field.
> >
> > I tried to use vtkImageAccumulate to achieve this goal, but
> > my program crashes on my input (actually, I don't know how
> > to specify on which of the arrays I want to apply. How
> > should I do it?)
> > When I tried to specify origin and spacing, I got similar result (seg
> fault)
> >
> >         vtkImageAccumulate *Accumulate = vtkImageAccumulate::New();
> >
> > Accumulate->SetInput(grid);
> >
> > Accumulate->Update();
> > <------- crashes here
> >         double *mean = Accumulate->GetMean();
> >
> >
> > Thank you!
> > ula
> >
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