How to Create a New Dataset
The following instructions explain how to create a new dataset.
This dialog allows the creation of a dataset (an HDF4 SDS or an HDF5 dataset).
The dataset can be a 1 to 32 dimension array of numbers, characters, or strings.
To create a dataset, it is necessary to define its name
, parent group, datatype, dataspace
(i.e., the dimensions). Optionally, the storage properties
can be specified.
The dataset will be created and filled with zeros. Data can be added with
the hdfedit tool, or by a program.
1) Dataset name and path
The name of the new dataset must follow the HDF5 name
rules (similar to the unix name rules). The name may contain almost
any characters, but it must not contain the path separator, '/'.
The dataset must be a member of some Group. The 'Add to group' selection
lists all the Groups in the file.
2) Datatype
The datatype specifies the type of the data elements of the array.
This Java-based tool only supports three datatypes: integer, float and string.
The size specifies the size of a single data point in bits such
as 32-bit integer or 64-bit float. The size of a float is either
32-bit or 64-bit. For HDF5, there are three byte order choices:
NATIVE, LITTLE ENDIAN and BIG ENDIAN. "NATIVE" byte order means that the
byte order is determined by the machine. The byte order cannot be
specified for HDF4.
3) Dataspace
The dataspece specifies number of dimensions (rank), current
dimension size and maximum dimension size. The dimension size is
separated by "x". For example, a 3D dataset might show the dimensions
as: 20 x 30 x 5.
The current size must be greater than zero, and the maximum size
must be at least as large as the current size. A maximum size or
zero means the maximum size will be set to the current size. Setting the
maximum size to -1 will make the dimension "unlimited".
4) Storage layout and data compression
There are two options for storage layout: continguous or chunked.
The default storage layout is continguous. If chunked layout is
selected, the chunk size must be specified.
The dataset may be compressed with GZIP. The compression level is
ranged from zero (no compression) to 9 (highest compression). In HDF5,
if compression is selected then the dataset must be chunked.