[Freegis-list] compressing GML

[Daniel Calvelo Aros]

From: "michael gould" <gould at lsi.uji.es>
Sent: Wed, 20 Jul 2005 15:50:14 +0200
>
> Hi all,

Hola, Michael.

> I am curious if people out there have made anyprogress in the area 
> of compression/decompression of GML for transport. ( Irecall a while 
> back someone complaining of GML&#8217;s verbosity, and 
> othersreplying that&#8217;s ok, you can always gZip it&#8230;)

Indeed, all SGML-derived variants are very compressible. That's why
OpenOffice's format is XML-inside-zip-archive.

gzip compression for transport should be transparently handled by the web
server. It is specified in HTTP 1.1 at least; see e.g. mod_gzip for Apache. 

The point is that the http *client* should 1) advertise gzip capabilities when
sending requests, using 'Accept-encoding: gzip' in the headers sent along the
GET/POST request and 2) handle decompression. Modern browsers do. I don't know
about current WFS/WMS clients. 

Do try to sniff the connection to find out.

Hope this helps.

Daniel.