An HDF5 group is a grouping structure containing instances of zero or more groups or datasets, together with supporting metadata. An HDF5 dataset is a multidimensional array of data elements, together with supporting metadata. The data elements can have many types, including arbitrary structured records. Other HDF5 data structures include datatype , dataspace , attribute and property list . A datatype describes the storage format of individual data points of a data set and a dataspace describes the positions of the elements of a dataset.
Attributes are small datasets to be attached to primary datasets or groups as metadata information.
In VisAD, numerical data objects are finite approximations to idealized mathematical objects such as real numbers, vectors, sets and functions. Thus every Data object has a MathType , which indicates the type of mathematical object that it approximates. SetType FunctionType Figure 1. Irregular2DSet Irregular3DSet Function Field FlatField Figure 2. The VisAD Data hierarchy 4.