Any object in an HDF file can have annotations associated with it. However, with the SD and Vset (VData/Vgroup) interfaces, user-defined attributes are available, which can be used instead.
There are a number of types of annotations:
- Labels are assumed to be short strings giving the "name" of a data object.
- Descriptions are longer text segments that are useful for giving more indepth information about a data object.
- File annotations are assumed to apply to all of the objects in a single file.