# Are multiple "PointData" datasets supported using VTKHDF "ImageData".

**URL:** https://discourse.vtk.org/t/are-multiple-pointdata-datasets-supported-using-vtkhdf-imagedata/11418
**Category:** Support
**Created:** [May 9, 2023, 7:11pm UTC](https://discourse.vtk.org/t/are-multiple-pointdata-datasets-supported-using-vtkhdf-imagedata/11418 "2023-05-09T19:11:23Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![HendersonSC](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hendersonsc/32/7059_2.png) [@HendersonSC](https://discourse.vtk.org/u/HendersonSC)
#### Post date: [May 9, 2023, 7:11pm UTC](https://discourse.vtk.org/t/are-multiple-pointdata-datasets-supported-using-vtkhdf-imagedata/11418/1 "2023-05-09T19:11:23Z")

</div>

The documentation for VTKHDF seems to suggest that the following code:

```auto
import h5py
import numpy as np

with h5py.File("wtf.hdf",'w') as hdffile:

        # write support data
        vtkhdf_group = hdffile.create_group("VTKHDF")
        vtkhdf_group.attrs.create("Version", [1, 0])

        vtkhdf_group.attrs.create("Type",np.string_("ImageData"))
        whole_extent = (0, 3, 0, 1, 0, 0)
        vtkhdf_group.attrs.create("WholeExtent", whole_extent)

        vtkhdf_group.attrs.create("Origin", (0.0, 0.0, 0.0))
        vtkhdf_group.attrs.create("Spacing", (1.0, 1.0, 1.0))
        vtkhdf_group.attrs.create("Direction", (1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0))

        # create the pointdata group and the dataset inside it
        field_data_group = vtkhdf_group.create_group("PointData")
        field_data_group.attrs.create('Scalars', ["D1","D2"],) ## Doesn't work
        dset1 = field_data_group.create_dataset('D1',dtype=np.uint8,shape=(2,4))

        dset1[:, :] = np.reshape([0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0],(2, 4))

        dset2 = field_data_group.create_dataset('D2',dtype=np.uint8,shape=(2,4))

        dset2[:, :] = np.reshape([7.0,6.0,5.0,4.0,3.0,2.0,1.0,0.0],(2, 4))

```

would generate a valid file with two PointData datasets, but when viewing is attempted in Paraview 5.1.1 it crashes. This is just to confirm I am reading the limited documentation correctly.

---

<div class="post-metadata">

### Author: ![danlipsa](https://discourse.vtk.org/user_avatar/discourse.vtk.org/danlipsa/32/390_2.png) [@danlipsa](https://discourse.vtk.org/u/danlipsa)
#### Post date: [May 9, 2023, 8:10pm UTC](https://discourse.vtk.org/t/are-multiple-pointdata-datasets-supported-using-vtkhdf-imagedata/11418/2 "2023-05-09T20:10:37Z")

</div>

I did not look at your dataset yet.

Yes, those correspond to multiple point data fields. You can take a look at[https://gitlab.kitware.com/danlipsa/vtkxml-to-vtkhdf](https://gitlab.kitware.com/danlipsa/vtkxml-to-vtkhdf)  
as an example that converts VTK XML datasets to VTK HDF datasets for image data and unstructured grid.

There is a VTK test you can try:  
ctest -R HDFReader

That test reads the following HDF image dataset you can inspect, maybe you figure out what is the issue:  
build/ExternalData/Testing/Data/mandelbrot-vti.hdf

Dan