Thanks for this very useful feedback! I have not heard the concern
during the OGC meeting where I was, but metadata was discussed during
many sessions. I can't remember Simon mentioned it during the ebRIM
discussion and I can't remember anyone else mentioning it... In fact
the lack of a free text search option could be a mayor constraint. I
there no way around this issue? I can also see benefits in the ebRIM
approach and have thus not made objections to the proposal. The free
text issue is definitely one that needs further discussion before a
final decision is made.
We have not decided anything on the ebRIM profile yet as it all needs
to be discussed further at OGC in anyway. For now we will concentrate
on the ISO profile and most likely also on the ESA proposed Earth
Observation profile (implementing client support to EO profile based
catalogs). Any ebRIM work would I think for sure not happen before
next year and from your message I can see that there's still enough
to be discussed before really moving towards ebRIM support.
Thanks a lot,
On Jul 18, 2006, at 8:39 AM, John.Hockaday@... wrote:
> Hi Jeroen,
> I hope you don't mind me taking this discussion directly to you.
> If you like
> please send it to the GeoNetwork developers lists.
> I have noticed that you are on the OGC ISO 19115/19119 revision
> working group
> and that you have a great deal to do with the development of
> GeoNetwork. As
> you know I am very involved with the implementation of ISO 19100
> I expect that you are aware of the Edinburgh OGC recommendation
> that all
> Catalogue Services - Web (CSW) should be implemented using ebRIM.
> I notice
> that GeoNetwork doesn't use the ebRIM implementation.
> GeoNetwork stores the metadata as a single object in a RDBMS. This
> is great
> because it means that the essential free text search can be done on
> column of these objects. This search is covered by the "anyText"
> element of CSW. I have found from my 12 years of management of
> search metadata systems that the majority (~80-90%) of searches are
> free text
> on any component of the metadata. That is, the equivalent of
> "anyText" is
> used for the majority of metadata searches.
> However, ebRIM takes a subset of the metadata and stores this in RDBMS
> tables. Searches are then done directly on this subset. Once the
> is identified by the search results of this subset, the metadata
> record can
> be presented to the user.
> ebRIM does not implement the "anyText" and this is a major flaw of
> the ebRIM
> CSW implementation. It is likely that a majority of the metadata
> content is
> not accessed for search results and therefore it will not return
> the correct
> hits expected by the users.
> A data custodian is not likely to fill out an optional metadata
> unless they feel that the element is essential to describe their
> data. If
> they identify this importance then it is also important that this
> element be
> available for users to search. If ebRIM does not index these optional
> elements than it will not be meeting the expectations of the data
> I have voiced my concerns to Simon Cox who I believed tabled them at
> Edinburgh. However, this was voted down and so any implementation
> of ebRIM
> for CSW is likely to not meet the users existing expectations and
> If GeoNetwork was to adopt the ebRIM implementation of CSW then I
> that a major part of GeoNetwork's functionality will be lost. Do
> you expect
> that GeoNetwork will adopt the ebRIM implementation of CDW? If so
> when will
> this work be done?
> How do you feel about this reduction in essential usability of
> John Hockaday
> Geoscience Australia
> GPO Box 378
> Canberra ACT 2601
> (02) 6249 9735