The PICES Technical Committee on Data Exchange (TCODE) is developing
the PICES Metadata Federation (PMF). The project's mission is to
build a one-stop utility for public search, access and delivery
of international marine ecosystem data through the Internet. This
mission is to be achieved by federating national, governmental,
academic and private metadatabases (collections of information describing
and providing access to datasets, publications, cruise reports,
etc.) using common standards and protocols.
Federation is a process of joining for mutual benefit. For example,
suppose Provider 1 produces Product A, and Provider 2 produces Product
B. In a non-federated system, a consumer wanting Product A would
have to get it from Provider 1, and Product B would only be available
from Provider 2. However, if Providers 1 and 2 are willing and able
to cooperate, each can maximize the distribution of its own product
by also offering it through the other provider, and particularly
through a common Provider 3 that has no products of its own to offer
but serves as a clearinghouse for a number of providers. This is
a federation.
The federation promotes efficiency for the provider and the consumer.
Each provider effectively boosts its product line by having available
more products without actually having to produce them. The consumer
benefits by being able to locate more products without having to
visit more than one provider. The greater intention of this project
is to federate the marine metadata holdings of all PICES member
countries using a central clearinghouse.
To enable an Internet browsing
client to search and discover information through a federated
metadatabase, four elements must be in place. First, the client
must be able to communicate with the clearinghouse using normal
web communications. Second, the clearinghouse must offer an
Internet communication protocol and associated utilities that
permit search and discovery of federated metadata records.
Third, each federated partner must maintain metadata records
using a standard that is supported by the communication protocol.
Fourth, each federated partner must serve the Internet through
a server that is conversant in the communication protocol
and that hosts metadata records in the proper standard.
Figure
1. A successful Internet federation requires partners to use
common metadata coding standards and share a common communication
protocol with the clearinghouse.
HISTORY
The precursor to this project was another PICES
TCODE development, the North Pacific Ecosystem Metadatabase (NPEM).
The NPEM was started in 1997 as the Bering Sea Ecosystem Biophysical
Metadatabase (BSEBM) by Bernard Megrey and Allen Macklin of the
U.S. National Oceanic and Atmospheric Administration (NOAA). Their
impetus was the U.S. National Research Council's declaration that
a serious impediment to advance of Bering Sea marine ecosystem knowledge
was the lack of a central catalogue of research results and observations.
Funding for the BSEBM came from NOAA and, later, from the North
Pacific Research Board. PICES' involvement in the project grew out
of the PICES/CoML/IPRC Workshop on "Impact of Climate Variability
on Observation and Prediction of Ecosystem and Biodiversity Changes
in the North Pacific" (PICES Scientific Report No. 18, 2001).
A recommendation of the workshop was to ensure that the time-series
information and scientific contacts identified at the workshop be
recorded and updated in the North Pacific Ecosystem Metadatabase
in which TCODE had already placed the PICES long-term time-series
information. The meeting's participants endorsed the proposal that
the BSEBM be considered as the PICES North Pacific Ecosystem Metadatabase.
With the support of PICES, the metadatabase directors
obtained funds in 2002 for a three-year project to expand the scope
of metadata holdings from the Bering Sea to the North Pacific. As
the NPEM matured, it became evident that redundancies were occurring
in various Pacific Rim metadatabases. The redundancies were created
by importing each other’s metadata records to expand individual
metadata holdings. To resolve this problem, the project in 2004
began to develop a "federated" system, wherein a user
could access electronically the North Pacific Ecosystem Metadatabase
as well as the holdings of Ocean Data Centers and other national
and academic metadata archives in a single search.
With financial support from PICES and the National
Spatial Data Infrastructure Cooperative Agreements Program (CAP),
NPEM and the Korea Oceanographic Data Center
(KODC) established partnership in an existing federation sponsored
by the U.S. Federal Geographic Data Committee (FGDC) called the
National
Spatial Data Infrastructure (NSDI) Clearinghouse. The NSDI Clearinghouse
requires metadata to be coded using the FGDC standard, and it uses
ISite, an instance of the Z39.50 communication protocol, for queries
and exchanges. For KODC, an intermediate step was to translate essential
metadata records into English and recode them from the Directory
Interchange Format (DIF) to the FGDC metadata standard. With this
done, the KODC-NPEM metadata team completed registration of their
respective nodes on the NSDI Clearinghouse in 2005, enabling searches
of their collective holdings from a single search command. In that
same year, the Pacific Research Institute
of Fisheries and Oceanography (TINRO-Centre) in Vladivostok,
Russia, joined the federation. Again with financial assistance from
PICES and NSDI CAP in separate programs in 2006 and 2007, respectively,
Japan’s Marine Information
Research Center (MIRC) and China’s National Marine Data
and Information Service National
Marine Data and Information Service (NMDIS) became members.
Because of security issues in China and the U.S.A.,
PICES rented an Internet server, ADHOST, in 2008, to serve the PMF
and other PICES information. Some PMF nodes are mirrored on this
site, some are found only on this site. Figure 2 shows the PICES
nodes of the NSDI Clearinghouse in August 2008. An up-to-date listing
can be obtained by browsing the “Hourly Status of International
Clearinghouse Nodes” at the NDIS Clearinghouse Registry.
Figure
2. The Clearinghouse Registry(http://registry.fgdc.gov/serverstatus/)
provides the hourly status of the hundreds of metadata servers,
including the PICES nodes shown here, that are part of the clearinghouse.
This example is from August 11, 2008.
As part of this project, TCODE is
developing an independent ADHOST clearinghouse for PICES nodes only.
When completed, this PICES Clearinghouse will be registered with
the NSDI Clearinghouse and others to create a clearinghouse of clearinghouses.
This will give the Internet user a very powerful tool for searching
much of the world’s cataloged geospatial information.
Information on how to code metadata and configure
a server to become a registered member of the PMF is published in
PICES
Technical Report No. 1 Metadata Federation of PICES Member Countries
SEARCHING
THE NSDI CLEARINGHOUSE
Anyone with Internet access and a browser can
search
the NSDI Clearinghouse. Figure 3 shows the simplified search page.
Advanced and legacy search interfaces also are available by selecting
appropriate links. On the simplified search page, any or all of
the active metadata nodes can be selected to limit the range of
the search. In Fig. 3, the Server selector’s scroll bar has
been positioned to show the PICES nodes. Spatial, temporal and text
selection criteria can be entered, too. More elaborate searches
are available through the Advanced Search Interface.
Figure
3.The NSDI Clearinghouse Search Form. Two of the active PMF nodes are highlighted in the Server
selector, and “ice” is entered in the Free Text box.
Figure
4. Aggregate results matching the search criteria shown in Fig. 3.
PLANS
Continued development of the PMF will increase
the available information on marine ecosystems and improve the capability
to search for and deliver it. TCODE considers the PMF to be a vital
tool for PICES’ upcoming 10-year science effort of Forecasting
and Understanding Trends, Uncertainty and Responses of North Pacific
Ecosystems (FUTURE). According to the 2nd draft Implementation
Plan for FUTURE, TCODE is charged with enhancing the timely
availability of physical and biological data, supporting data management
needs and recommending data management policies (in close cooperation
with National Oceanographic Data Centers and the IOC International
Oceanographic Data Exchange program). The PMF fits many of these
requirements.
TINRO staff are leading the development of the
PICES Clearinghouse on the ADHOST server. This is particularly important
because it will give the PMF an Internet home that is not run by
the U.S. Government, thus reducing the political sensitivity. The
new clearinghouse is powered by a customizable version of GeoNetwork,
an open-source replacement for Isite. This new technology brings
many advantages. Among them, metadata coded in standards other than
FGDC can be mapped to a GeoNetwork, FGDC-compliant standard on import.
This will ease the burden on suppliers like MIRC and NMDIS that
use other standards. Figure 5 shows the search page being developed
for the ADHOST server. It is very similar to the NDIS search page,
but is tailored specifically for PICES use and offers multilingual
versions.
Figure
5. An early example of the search page being developed for the PICES
Clearinghouse on the ADHOST server.
TCODE anticipates that Fisheries
and Oceans Canada ’s (DFO) will become a member of the
PMF in the coming year. Canada, like some other members, has security
issues that hinder or prevent service of information for public
access. DFO has several hundred metadata records that will be stored
on PICES’ ADHOST server and indexed for distribution through
the PMF.
Finally, we invite agencies and institutions of
PICES member countries that are not yet members of the PMF to consider
joining. Having a single source at one’s fingertips with which
to locate the marine ecosystem information necessary to conduct
science and guide management is important to our world.
S. Allen Macklin
November 2008
Publications
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