Hi Pauline/All,
Sorry I left you off the previous response - should've used 'Hi All' like
everyone else does!
We're obviously not going to/cannot cope with all cases here!
However the plan is to build metadata on thredds datasets (19115) that:
1. have ThreddsMetadata group with DIF digital library elements (via Dave
Connell's DIF to ISO xslts),
2. have a similar but as yet not finalized ISO set of digital library elements
(but only in the Geonetwork side not netcdf-4.0 as XSLTs rather than Java/JDOM
will be used to make building the ISO elements easier) and
3. are available via Thredds OGC WCS and OGC WMS (we will use an existing
GeoNetwork OGC harvester for these)
Collection level datasets will be built and child/nested datasets will refer to
their parent through the ISO parentIdentifier element.
Also service metadata (19119) records will be built for the services offered by
the thredds catalog - service records will list the ids of the datasets they
deliver in the ISO 19119 operatesOn element.
I think we'll support anything that fits the CDM (but doesn't have metadata
elements exposed in the catalogue?) by getting the coordinate system info as
XML and using an XSLT (based on whatever builder was used) to create the
appropriate bits of the ISO records (but this isn't settled/done yet).
I'm planning to put more on this in a proposal on the GeoNetwork developers
site with hopefully more detail soon. http://trac.osgeo.org/geonetwork
Cheers and thanks!
Simon
________________________________________
From: Pauline Mak [Pauline.Mak@xxxxxxxxxxx]
Sent: Friday, 10 April 2009 10:41 AM
To: Richard Signell
Cc: Pigot, Simon (CMAR, Hobart); thredds@xxxxxxxxxxxxxxxx; Peter Blain
Subject: Re: [thredds] Running THREDDS on top of old OPeNDAP servers
Hi all,
Simon - this is exciting stuff!!! I was wondering - how are you
generating the ISO documents? Are you going to add extra information
into the THREDDS "Digital Library Metadata Elements" when referred to
making ISO19119 records for thredds services? I'm particularly
interested in the automatic extraction of geospatial boundaries. I was
hoping to use some standard document to extract this. I thought WCS
would be good for this, but it has just hit me (unfortunately, somewhat
late in this project) that it only works on a small subset (i.e. only
for regularly gridded datasets) :(
Looking at the catalog spec, it looks like the geospatial and temporal
extent is something that has to be hand-crafted. But given CDM can read
these values (and for more than just regularly gridded datasets), it
would seem to make sense if this could be automated somehow?
Interestingly, the NetCDF Subsetter's dataset.xml document (e.g.
http://opendap-ivec.arcs.org.au/thredds/ncss/grid/TERN_AUSCOVER/MODIS/L2/LPDAAC/aust/MOD13Q1.005/2000.02.18/MOD13Q1.2000.049.aust.005.b01.250m_ndvi.hdf.gz/dataset.xml)
will produce the required information, but, this is doesn't follow any
kind of metadata standards (as far as I know anyway).
Any suggestionsAs Rich was saying, do you have any "ISO thredds
catalogs" on a server, dev or otherwise that we can have a look at?
Cheers,
-Pauline.
Richard Signell wrote:
> Simon,
>
> This sounds extremely useful and I'd love to give it a try.
>
> Can you please tell us what the "trivial" changes are to NetCDF-Java?
>
> And do you have a real-life example of the catalog below that works
> with publicly available OpenDAP data?
>
> Thanks,
> Rich
>
> On Wed, Apr 8, 2009 at 8:28 PM, <Simon.Pigot@xxxxxxxx> wrote:
>> Hi Pauline,
>>
>> The following works ok for us (as an example - non-essential details
>> removed):
>>
>> <?xml version="1.0" encoding="UTF-8"?>
>> <catalog name="YOUR SITE OPeNDAP Catalog"
>> xmlns="http://www.unidata.ucar.edu/namespaces/thredds/InvCatalog/v1.0";
>> xmlns:xlink="http://www.w3.org/1999/xlink";>
>>
>> <service name="yoursiteopendap" serviceType="OpenDAP"
>> base="http://www.yoursite.com/dods/nph-dods/dods-data/"/>
>> <datasetScan name="climatology-netcdf" path="climatology-netcdf"
>> location="http://www.yoursite.com/dods/nph-dods/dods-data/climatology-netcdf";>
>> <serviceName>yoursiteopendap</serviceName>
>> <crawlableDatasetImpl
>> className="thredds.crawlabledataset.CrawlableDatasetDods" />
>> </datasetScan>
>> <datasetScan name="bluelink" path="bluelink"
>> location="http://www.yoursite.com/dods/nph-dods/dods-data/bluelink";>
>> <serviceName>yoursiteopendap</serviceName>
>> <crawlableDatasetImpl
>> className="thredds.crawlabledataset.CrawlableDatasetDods" />
>> </datasetScan>
>> </catalog>
>>
>> I'm not sure if its all documented somewhere - I worked it out the slow way
>> by poking around in the netcdf java code and hunting through the archives of
>> the thredds mailing list. There are also some trivial changes you need to
>> make to the code (in netcdf-java) to filter out some unwanted artifacts
>> created when the scan picks through the html from the OpenDAP server -
>> otherwise you end up with some strange, non-functional things in your
>> catalog. Maybe there is a better way to do the above?
>>
>> By way of introduction, we want this sort of catalog to work as part of a
>> thredds metadata harvester I'm adding to GeoNetwork which produces ISO19115
>> metadata records and ISO19119 records for thredds services. Its nearly at
>> the stage where it is working reliably but there are a few more issues I
>> need to solve and I'm still learning about Thredds :-)
>>
>> Cheers and I hope this helps,
>> Simon
>>
>> ________________________________________
>> From: thredds-bounces@xxxxxxxxxxxxxxxx [thredds-bounces@xxxxxxxxxxxxxxxx] On
>> Behalf Of Pauline Mak [Pauline.Mak@xxxxxxxxxxx]
>> Sent: Thursday, 9 April 2009 8:56 AM
>> To: thredds@xxxxxxxxxxxxxxxx
>> Subject: [thredds] Running THREDDS on top of old OPeNDAP servers
>>
>> Hi all,
>>
>> I'm figuring out ways to serve data using THREDDS on top of old OPeNDAP
>> servers. I'm aware that you can configure datasets based on a URL, but
>> that's for a single file... (correct me if I'm wrong!) However, are
>> there ways to apply to an directory? Sort of like a datasetScan +
>> filters for a directory URL? When poking through the THREDDS catalog
>> XSD, there's a crawlableDatasetImpl element. Is that the sort of things
>> I need to look at?
>>
>> Thanks,
>>
>> -Pauline.
>>
>> --
>> Pauline Mak
>>
>> ARCS Data Services
>> Ph: (03) 6226 7518
>> Email: pauline.mak@xxxxxxxxxxx
>> Jabber: pauline.mak@xxxxxxxxxxx
>> http://www.arcs.org.au/
>>
>> TPAC
>> Email: pauline.mak@xxxxxxxxxxx
>> http://www.tpac.org.au/
>>
>>
>>
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>
>
>
--
Pauline Mak
ARCS Data Services
Ph: (03) 6226 7518
Email: pauline.mak@xxxxxxxxxxx
Jabber: pauline.mak@xxxxxxxxxxx
http://www.arcs.org.au/
TPAC
Email: pauline.mak@xxxxxxxxxxx
http://www.tpac.org.au/
