How to generate a .template and .jigdo from an iso image?

[Marcelo M. Garcia]

Hi.

I'm interested in generating the .jigdo and .template from a .iso image. 
I couldn't find much information on this. It would be a straightforward 
process, just run "jigdo-file file.iso" and I would have my .jigdo and 
my .template.

The problem is doing like this, my .template has almost the same size of 
the .iso image. I noticed that the Fedora 11 x86_64 has only 11.1M. My 
question is how to do that? How to get a .template so small?

Where I can get a good documentation about jigdo-file? The official web 
site[1] it isn't very helpful.

Thanks

Marcelo

[1] http://atterer.net/jigdo/