The ISO-19115 & ISO-19139 confusion
The ISO19115-19139 standards seem to confuse many, many people. Here's a short attempt to clarify the situation :-) There is only one (1!) metadata standard for geographic data, and that is the ISO-19115 metadata standard. The ISO-19115 standard was originally released without a DTD or XML schema that could be used to validate such a metadata record (formatted as an XML document). It was decided by ISO TC211 to develop a specific implementation standard, called ISO-19139. This standard would have the form of a metadata scheme (an XSD document). The schema can be used to validate the structure of an ISO-19115 document. It has taken a long time for a good 19139 schema to be released. A final schema is still not available to date (04-2007).
To confuse things more, many software started implementing different versions of the ISO-19115 standard :( The GeoNetwork development team decided back in 2002 to use the Draft International Standard version of ISO-19115 (ISO-19115:DIS). This version of the standard (not yet standard at that point) provided a DTD and was as such the only version that could have a formal checking of its structure. GeoNetwork used (and still supports) short element names in its XML representation.
For GeoNetwork 2.1 we have now created a migration procedure to convert the ISO-19115:DIS formatted metadata into a structure that complies with the formal ISO-19115:2003 standard and that validates against the ISO-19139 schema as released on 4 May 2006 referred to as 'final Release candidate for TS'.
GeoNetwork opensource still supports the 19115:DIS format for backward compatibility, but it is foreseen that that format will be less exposed to users to facilitate transition to the new format and avoid a bit of confusion :-)
