Hi,
indexing (and searching) of fields is a somewhat complicated issue. I
have been digging out how it works for the last days and I'm planning to
update the documentation soon.
I work at the World Meteorological Organization in the WMO Information
System office (with David Thomas, a compatriot of yours, and Eliot
Christian) and we are working on improving the Geonetwork search
and adding SRU support. (via JZkit2)
At a glance, this is how searching and indexing works in GN.
(corrections are welcome should I be wrong here).
At indexing time a XSL transformation determines the fields that should
get indexed and the names of the indices. According to the schema of the
metadata-file being indexed, an XSL transformation is applied which
outputs the information to be indexed.
These files reside below web\geonetwork\xml\schemas\*\index-fields.xsl
A lucene document Object (java) is then created parsing the output from
the transformation above. After that the actual indexing takes place.
At search time, your query is also processed by a XSL transformation.
According to the type of search (Z39.50, CSW, old interface) etc.. one
of the XSL files in web\geonetwork\xml\search is used to transform your
query to an "internal" lucene query format which is in turn transformed
to actual Lucene Query Objects (java).
So, what you probably have to do is to change the latter files so that
your query is translated into a lucene query searching in the right
indexes.
In short, have a look at web\geonetwork\xml\search\lucene.xsl
hope this helps
Timo
--
Timo Pröscholdt
Program Officer, WMO Information System (WIS)
Observing and Information Systems Department
World Meteorological Organization
Tel: +41 22 730 81 76
Cell: +41 77 40 63 554
e-mail: tproescholdt@anonymised.com
Michael.Stegherr@anonymised.com a écrit :
Hi,
Maybe someone on the users list can help me with this:
When I'm entering a date in the Advanced Search "When?" section (in GeoNetwork 2.4.1) the following information is queried (in ISO19139 records):
"Identification Info / Metadata / Date stamp"
As far as I unstand the value of this is set automatically on creation of a record.
In my opinion it would be _very_ useful to query the value of the following entry instead:
"Identification Info / Date"
This would allow to search for updated records as well.
It looked like in the trunk version of GeoNetwork, the search has been already altered to search this field, by I may be mistaken.
Also the help says:
"The WHEN? section gives you the possibility to restrict your search in terms of temporal extent, indicating a specific range of time referred to the data creation or publication date"
It's a bit confusing to me. How are you using this search feature?
Cheers,
Michael