A web based Geographic Metadata Catalog for data description and discovery. It implements international standards (e.g. ISO19115/19139, ISO19115-3, Z39.50, CSW 2.0, OGC). It originates from the United Nations and is used by many governments as geoportal software Source code available on github https://github.com/geonetwork/
GeoNetwork for AU/NZ users
GeoNetwork 2.10.5 with Australia/New Zealand Metadata Profiles and NICTA National Map as map viewer - see screenshots. Beta version of GeoNetwork 3.1.x with Australia/New Zealand Metadata Profiles coming shortly.