The purpose of NISO Z39.87 is to define a standard set of metadata elements for digital images .
Standardizing the information allows users to develop, exchange, and interpret digital image files. It has been designed to facilitate interoperability
between systems, services, and software, as well as to support the continuing access to digital image collections and their long-term management.
The design objectives of this NISO initiative are to define a metadata set that interoperates with and meets the goal outlined by the DIG35 metadata
standard. To that end, the NISO group has adapted the original DIG35 goals as follows:
The main categories of metadata elements can be summarised and organised as follows:
- Interchangeable: The NISO metadata set is based on a sound conceptual model that is both generally applicable to many applications and assured to be consistent over time.
- Extensible and scalable: The NISO metadata set enables application developers and hardware manufacturers to utilize additional metadata fields.
This allows future needs for metadata to be fulfilled with limited disruption of current solutions.
- Image file format independent: The NISO metadata set does not rely on any specific file format and can therefore be supported by many current
and future file formats and compression mechanisms.
- Consistent: The NISO metadata set works well with existing standards and it is usable in a variety of application domains and user situations.
- Network-ready: The NISO metadata set provides seamless integration with a broad variety of systems and services. Integration options include
database products and the utilization of XML schemas (the recommended implementation method).
- Basic Image Parameters: Format, File Size, Compression, Colour Space, etc.
- Image Creation: Source Type, Producer, Scanning System for Capture, Digital Camera Set-up for Capture.
- Imaging Performance Assessment: Spatial metrics (sampling frequency, image dimensions, source dimensions),
Energetics (bits per sample, colour map, white point, etc), target data (type, image data, performance data).
- Change History: Image processing (date, source data, software), previous image metadata.