VTK XML Reader/Writer Information Format

Overview

The vtk xml data file readers / writers store certain vtkInformation entries that are set on vtkAbstractArray’s GetInformation() object. Support is currently limited to numeric and string information keys, both single- and vector-valued. Only the information objects attached to arrays are written/read.

Array Information

Array information is embedded in the <DataArray> XML element as a series of <InformationKey> elements. The required attributes name and location specify the name and location strings associated with the key – for instance, the vtkDataArray::UNITS_LABEL() key has name="UNITS_LABEL" and location="vtkDataArray". The length attribute is required for vector keys.

<DataArray [...]>
  <InformationKey name="KeyName" location="KeyLocation" [ length="N" ]>
    [...]
  </InformationKey>
  <InformationKey [...]>
    [...]
  </InformationKey>
  [...]
</DataArray>

Specific examples of supported key types:

vtkInformationDoubleKey

<InformationKey name="Double" location="XMLTestKey">
  1
</InformationKey>

vtkInformationDoubleVectorKey

<InformationKey name="DoubleVector" location="XMLTestKey" length="3">
  <Value index="0">
    1
  </Value>
  <Value index="1">
    90
  </Value>
  <Value index="2">
    260
  </Value>
</InformationKey>

vtkInformationIdTypeKey

<InformationKey name="IdType" location="XMLTestKey">
  5
</InformationKey>

vtkInformationStringKey

<InformationKey name="String" location="XMLTestKey">
  Test String!
Line2
</InformationKey>

vtkInformationIntegerKey

<InformationKey name="Integer" location="XMLTestKey">
  408
</InformationKey>

vtkInformationIntegerVectorKey

<InformationKey name="IntegerVector" location="XMLTestKey" length="3">
  <Value index="0">
    1
  </Value>
  <Value index="1">
    5
  </Value>
  <Value index="2">
    45
  </Value>
</InformationKey>

vtkInformationStringVectorKey

<InformationKey name="StringVector" location="XMLTestKey" length="3">
  <Value index="0">
    First
  </Value>
  <Value index="1">
    Second (with whitespace!)
  </Value>
  <Value index="2">
    Third (with
newline!)
  </Value>
</InformationKey>

vtkInformationUnsignedLongKey

<InformationKey name="UnsignedLong" location="XMLTestKey">
  9
</InformationKey>