SGML or XML?

[Doig Jonathan <doigj@epa.nsw.gov.au>]

Thanks to Simon Cox for his summary of the metadata encoding
state-of-play from AW3TC.

One small point to clarify: XML is also a restricted form of SGML, but a
far more flexible one than HTML. The goal of XML is to enable generic
SGML to be served, received, and processed on the Web in the way that is
now possible with HTML.

>From a quick look, I understand that XML is a version 1.0 working draft
(Mar 97) which has not yet been approved by the W3C SGML editorial
board.
So it may be a bit early to start using it now.

For background, see http://www.gca.org/conf/xml/xml_what.htm What is
XML?

Jonathan Doig
__________________________________________________________
DoigJ@chat1.epa.nsw.gov.au       http://www.epa.nsw.gov.au
GIS Specialist, Economics & Environmental Reporting Branch
New   South   Wales   Environment   Protection   Authority

> My understanding of the current state-of-play/expectations 
> about how this will all be implemented contains the following layers:
>
> various metadata semantics (DC, ANZLIC, FGDC ... and combos)
> expressed using PICS-ng ("next generation", believe it or not!) 
>	(attribute,value) syntax
> encoded variously - but XML looks like getting the guernsey 
>	as the main human-readable/web-retrievable format, 
>	with z39.50 gateways providing compatibility with that universe. 
>
> I like the look of XML - it is another metalanguage like SGML, 
> but is more restricted/prescriptive than SGML so parsers will 
> be easier to implement etc, but of course being a metalanguage 
> it is much richer than HTML.