Rationale for GedML

Why do it?

XML provides a standard way of representing structured data of any kind. Genealogical data is an example of such data, and the current standard, GEDCOM, uses a proprietary encoding technique. Some of the limitations with GEDCOM are:

• It is not easy to write applications that manipulate GEDCOM files - especially if you want to handle any correct GEDCOM file, to report errors when the file is incorrect, and to process large files quickly.

• The handling of international character sets is cumbersome and not in line with modern standards adopted by the IT industry (specifically, UNICODE)

• It is not possible to define cross-references linking data in different GEDCOM files

• GEDCOM files are not suitable for viewing directly on the Web (though it could be done with an appropriate plug-in): XML allows them to be viewed and browsed (and searched) directly, either through scripts written in a language such as JavaScript, or through XSL stylesheets.

Potential benefits

• easier programming for GEDCOM software developers, because there are a lot of standard (and fast) XML tools around. Many tasks, such as extracting GEDCOM data into a form suitable for input to a spreadsheet, have traditionally required special-purpose programs to be written. Using XML as a basis, such tasks can be done by writing a simple XSL stylesheet.

• no more need to worry about character set issues; they are all handled by the XML infrastructure. (XML is based on Unicode with mechanisms to support other encodings).

• a standard mechanism for embedding multimedia objects

• a mechanism for handling rich text in notes fields, e.g. variable fonts, bold and underline, and perhaps tabular material. It should also be possible to allow hyperlinks from the text of a notes field, for example where the text contains a reference to a person or place

• a powerful linking mechanism for defining relationships between objects whether in the same file, or in different files. There are two main ways that cross-file links could be used:

  1. To split your own data into multiple files, perhaps representing different branches of your family
  2. To create links between your data files and someone else's, which might be anywhere on the web.

• The ability to store your data directly on a web site, viewed through a special GEDCOM viewer (perhaps a Java applet), rather than translating it into a separate format (HTML) for viewing on the web. (This could be done today, but will be easier with an XML-based GEDCOM, because Java has class libraries that understand XML.)

• Intelligent indexing on web-based search engines. The standard search engines are starting to become XML-aware, so they will be able to index GedML files intelligently, distinguishing for example between Ireland as a surname and Ireland as a country. Instead of just searching for sites that mention Ireland, you will be able to search for sites containing genealogical data referring to the surname Ireland.