Re: [greenstone-devel] Classifiers

From Stefan Boddie
DateTue, 22 Jul 2003 14:39:49 +1200
Subject Re: [greenstone-devel] Classifiers
In-Reply-To (OF0DABC192-75FA18E0-ON69256D64-000E80D2-69256D64-000E8101-ntu-edu-au)
Hi Stephen,

I just read through this again (didn't really understand it the first time)
and I think it's a great idea. One of the biggest problems with Greenstone's
classifiers is that they don't scale to large collections well and this
seems like a simple way to improve that problem.

In theory it's certainly possible for the greenstone runtime system to
display classifications that have hlists at more than just the top level.
I'd need to do some testing to be sure though as I've not tried.

I'm not sure if extending AZCompactList is the best approach or if starting
from scratch would be better. If I did it I'd probably start afresh as
whenever I look at I get a headache :)

Anyway, I'll add this to my TODO list and have a go at it sometime if nobody
else feels the inclination to do it first. If you do get something like this
going please let us know.


P.S. On further reflection it seems like you might be able to get something
like this working more easily in the short term by customizing the Hierarchy
classifier a little rather than AZCompactList. You'd need to specify your
structure explicitly in one of the weirdly formatted hfile's though. There's
already an "hlist_at_top" option to the Hierarchy classifier that allows you
to force the top level of the hierarchy to be an hlist. It's probably not
too difficult to hack the code to make other levels hlists too.

----- Original Message -----
From: <>
To: <>
Sent: Tuesday, July 15, 2003 2:38 PM
Subject: [greenstone-devel] Classifiers

> Hi,
> We have a number of documents with a number of metadata fields.
> When browsing classifications it would be good to limit the number of
> displayed, and have those items sorted.
> Is there a way to create a classifier that works on two independant
> metadata fields;
> The top level being a a-z hlist split into groups as required (a-k l-z
> 0-9)(main Metadata field)
> The next level being a compact list (bookshelf icon) (main metadata field)
> the next level being hlist a-z split (a-k l-z 0-9) as required metadata
> field 2
> The bottom vlist being the leaves; sorted by the metadata field 2.
> AZCompactList seems to go some of the way- but I am unsure how to change
> to get the extra two levels (Or and arbitary number of levels = 2*number
> metadata fields - with the A-Z Hlists dissapearing if required...)
> Is there a way to do this? It will become more useful as the number of
> documents increase - especially where many have the same metadata values.
> Regards,
> Stephen
> PS I am trawling through to get my head around it.
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