Equivalent fields in these formats (for some there are available convertors): http://www.dlib.org/dlib/january00/chandler/01chandler.html
Alexandria Digital Library Metadata + Crosswalk scripts: http://www.alexandria.ucsb.edu/public-documents/metadata/index.html
ECAI Metadata Standards: http://www.ecai.org/documentation/ecai_metadata_standard.html
EU INSPIRE DIRECTIVE - establishing an INfrastructure for SPatial InfoRmation? in the European Community
Use of ISO standards (ISO 19115 XML and DublinCore?).
They have online editor for ISO-19115, and OGC Catalog Service CSW.
Topic Categories for maps:Spatial Data Themes INSPIRE
Omeka is a free, simple to use and simple to install (PHP+MySQL) open-source system for online cataloguing, publishing, sharing and annotating of historical documents - targeted to libraries, museum and archives. It supports DublinCore and OAI-PMH and is extensible via plug-ins. More info at http://omeka.org/
You can try it and directly use it also online via the cloud service: http://omeka.net/.
Online open-source catalogue implementing OAI-PMH and OGC CSW, web interface for editing ISO metadata.
Desktop Java application for editing metadata (ISO) (which are stored as files in the directory).
FGDC/GEODEX Metadata Editor saving records in MySQL database. Developed from "Building a Globally Distributed Historical Sheet Map Set" grant. It also contains GDAL2Tiles binary for cutting map files into Google Earth tiles.
Online MARC Editor with support for OAI, Z39.50, ... Possibility to use the project as an online service.
Koha is an open-source integrated library system (ILS): http://www.koha.org/
DublinCore: DCMI Box: documentation
Gonzalez J.A.; Problems That Arise When Providing Geographic Coordinate Information for Cataloged Maps; Coordinates, Coordinates, Series B, No.8, ISSN: 1553-3255; Access article in PDF
Our online tools for generating MARC21 Metadata for old maps (before 1850):
Tools working with map series and prepared sheet indexes: