I only caught the end of this thread which was beginning to talk about
geo-search syntax in CQL so I polled the opinion of two of my Geo
colleagues. I thought their comments might be useful.
[ Ah, I've just been through the list archives and see this should've been
part of the CQL+GEO thread. never mind. ]
From Philip Abrahamson <[log in to unmask]>:
Something that should be noted here is that there are a number of
different geographic search relationships (GEO attribute set defines:
Overlaps, Fully Enclosed Within, Encloses, Fully Outside Of, Near, in
addition to the normal range attributes <,>,etc), and the "within"
operator is not a required operator in the GEO /profile/, but the
"Overlaps" operator is, which is somewhat more useful.
The GEO attribute set "Near" attribute is fundamentally flawed because
it leaves the definition of "Near" up to the Server, rather than the
client. One server may define near to be 10km away, and a different
server could define it to be a country away.
Instead of the near attribute, this should be achieved through a
proximity sort option.
One of the biggest issues I have with Z is the lack of sort options.
What would be very useful would be the ability to use a presorted index,
such as relevance, or proximity, and then to apply special "post-sorts"
to the limited result set of say 100-1000 results - e.g. a proximity
sort to follow a pre-sorted relevance sort.
From Eddie Boyle <[log in to unmask]>:
Philip knows more than me about this sort of thing, but from what I can
gather in the thread, what Mike is saying seems sound.
From my perspective in working with the Z39.50 GEO profile for GoGeo, the
*profile* caters for this sort of range searching very well, but the actual
implementation of and support for this profile in applications is patchy
(even in Isite).
Mike also is only mentioning 'within' relation operators - but in a geo
sense others are needed, including overlap and proximity operators.
Perhaps SRW needs to cater for the geo crowd by looking closely at the
current Z39.50 GEO profile?
Ben Soares tel: +44 (0)131-651 1238
EDINA, Edinburgh University Data Library fax: +44 (0)131-650 3308
Main Library Building, George Square email: [log in to unmask]
Edinburgh EH8 9LJ, Scotland, UK www: http://edina.ac.uk/
"Hmmm, that makes no sense to me...
But then you are very small, perhaps you're right." -- Treebeard