CDI field by pengxiang

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									        6Th Framework of EC DG Research




“Structuring the European Research Area” Specific Programme
                Research Infrastructures action




             Common Data Index (CDI)

                      Version 1.6

                    Metadata Format

                  Documentation: 5.00
Document revisions
Version   Date         Status   Author(s)    Description
1.0       2005-06-30   Final    Sea-Search   Documentation of CDI V0 format and
                                technical    XML coding
                                partners
2.0       2007-01-30   Draft    SeaDataNet   Updated documentation of CDI V0
                                technical    format and XML coding
                                partners
3.0       2007-06-30   Final    SeaDataNet   Updated documentation of CDI V0
                                technical    format and XML coding
                                partners
4.0       2010-02-11   Final    MARIS        Documentation upgraded to CDI V1
                                             including GML and Service Bindings
                                             extensions, instrument multiplicity, and
                                             spatial resolution / frequency to suit a.o.
                                             the Geo-Seas project and the EMODNET
                                             Hydrography pilot.


5.0       2010-06-10   Final    MARIS        Documentation upgraded to CDI V2.




                                        2
Content


0.     Introduction

1.     Logical description of CDI metadata format
1.1.   Granularity and definition
1.2.   The ISO 19115 standard as basis
1.3.   The CDI V2 format and elements

2.     Common Vocabularies, EDMO and EDMERP

3.     How to prepare and submit CDI entries

4.     References

5.     Annexes




Important Remark:
All documentation, libraries and software tools, which are described in this document,
can be found online from the SeaDataNet website: http://www.seadatanet.org




                                            3
0.    Introduction

Multidisciplinary oceanographic and marine data are collected by thousands of research
institutes, governmental organizations and private companies in the countries bordering
the European seas using various heterogeneous observing sensors installed on research
vessels, submarines, aircraft, moorings drifting buoys and satellites. The various sensors
measure physical parameters (temperature, salinity current, sea level, optical properties,
magnetic field, gravity), chemistry, biology, seabed characteristics, seabed depth etc. The
data are collected at a very considerable cost and are of prime value because they are the
reference for any study and, if lost, cannot be remade.

This data and information is very important for research, but also for monitoring,
predicting and managing the marine environment, assessing fish stocks and biodiversity,
offshore engineering, controlling any hazard or disaster, and the tourist industry. They
support the execution of international protocols, conventions and agreements, which have
been signed by coastal states for protection of the seas, such as OSPAR, HELCOM and
the Bucharest and Barcelona conventions. They are essential for implementation of
Europe‟s environmental policy concerning Integrated Coastal Zone Management
(ICZM), the Water Framework Directive, and the new Marine Strategy Directive. Overall
there are many thousands of users, based in the research sector, government and industry.

SeaDataNet is a leading infrastructure in Europe for marine & ocean data management.
It is actively operating and further developing a Pan-European infrastructure for
managing, indexing and providing access to ocean and marine data sets and data
products, acquired via research cruises and other observational activities, in situ and
remote sensing. The basis of SeaDataNet is interconnecting 40 National Oceanographic
Data Centres and Marine Data Centers from 35 countries around European seas into a
distributed network of data resources with common standards for metadata, vocabularies,
data transport formats, quality control methods and flags, and access. Thereby most of the
NODC‟s operate and/or are developing national networks to other institutes in their
countries to ensure national coverage and long-term stewardship of available data sets.

The majority of data managed by SeaDataNet partners concerns physical oceanography,
marine chemistry, hydrography, and a substantial volume of marine biology and geology
and geophysics. These are partly owned by the partner institutes themselves and for a
major part also owned by other organizations from their countries.

The SeaDataNet infrastructure is implemented with support of the EU via the EU FP6
SeaDataNet project to provide the Pan-European data management system adapted both
to the fragmented observation system and the users need for an integrated access to data,
meta-data, products and services. The SeaDataNet project has a duration of 5 years and
started in 2006, but builds upon earlier data management infrastructure projects,
undertaken over a period of 20 years by an expanding network of oceanographic data
centres from the countries around all European seas. Its predecessor project Sea-Search
had a strict focus on metadata. SeaDataNet maintains significant interest in the further



                                             4
development of the metadata infrastructure, extending its services with the provision of
easy data access and generic data products.

The SeaDataNet architecture has been designed as a multi-disciplinary system from the
beginning. It is able to support a wide variety of data types and to serve several sector
communities. SeaDataNet is willing to share its technologies and expertise, to spread and
expand its approach, and to build bridges to other well established infrastructures in the
marine domain.

Therefore SeaDataNet has developed a strategy of seeking active cooperation on a
national scale with other data holding organisations via its NODC networks and on an
international scale with other European and international data management initiatives and
networks. This is done with the objective to achieve a wider coverage of data sources and
an overall interoperability between data infrastructures in the marine and ocean domains.

Recent examples are e.g. the EU FP7 projects Geo-Seas for geology and geophysical data
sets, UpgradeBlackSeaScene for a Black Sea data management infrastructure, CaspInfo
for a Caspian Sea data management infrastructure, the EU EMODNET pilot projects, for
hydrographic, chemical, and biological data sets. All projects are adopting the
SeaDataNet standards and extending its services. Also active cooperation takes place
with EuroGOOS and MyOcean in the domain of real-time and delayed mode metocean
monitoring data.

An important objective of the SeaDataNet infrastructure is to provide transparent access
to the distributed data sets via a unique user interface and download service.

In the SeaDataNet V1 architecture the Common Data Index (CDI) V2 metadata service
provides the link between discovery and delivery of data sets. The CDI user interface
enables users to have a detailed insight of the availability and geographical distribution of
marine data, archived at the connected data centres. It provides sufficient information to
allow the user to assess the data relevance. Moreover the CDI user interface provides the
means for downloading data sets in common formats via a transaction mechanism.

The Common Data Index (CDI) has been initiated in the EU FP5 Sea-Search project, and
further developed and upgraded as part of the EU FP6 SeaDataNet project. Meanwhile
considerable work has been undertaken to define the CDI metadata format (XML) and
XML schema (XSD) as an extended marine profile of the ISO 19115 standard for
geographical data sets, and to develop Common Vocabularies, entry tools and services
for validation and retrieval of the CDI XML records.

The format, schema and associated tools are governed by the SeaDataNet Technical Task
Team (TTT). Extensions and other updates are undertaken by the TTT, but also in
cooperation with external experts. Especially applying the CDI V2 for an extending range
of ocean and marine data types, as planned and on-going in the associated projects, can
bring forward additional requirements.




                                              5
The Common Data Index (CDI) metadatabase thus provides an index to individual
datasets, managed and archived at connected data centres. It contains the metadata of
individual measurement data sets with key fields (what, where, when, how, who etc.). It
also provides the linking pin from the discovery services towards the delivery services,
because each CDI record has a direct relation to the data set, to which the users can
request access. Users can freely search and browse the CDI discovery services and
identify relevant data sets.

This documentation gives a logical description of the current CDI V2 format and its
elements. It is decided by the SeaDataNet TTT to „freeze‟ this version of the CDI V2
format as the core CDI V2 format. Any future extensions, possibly required when
analyzing the implementation of the CDI concept for every marine discipline, will be
included in an appendix to the core CDI V2 format.

In this documentation each content element of the core CDI V2 format is described and it
is explained how each element should be completed contentwise. CDI records are
produced and exchanged as XML files, that validate (=parse) to the CDI V1 XML
Schema. The XML Schema, the XML coding per content field and examples of CDI
XML files are part of this documentation, but included in separate Annex files that can be
downloaded from the SeaDataNet website. This way all XML tags, and syntax and
semantics, to be used for preparing CDI XML records, are documented. Furthermore it is
described how CDI XML records can be generated by data centres for their data
holdings. An important tool is the MIKADO software, that is maintained by SeaDataNet,
and available free of charge to support manual and automatic generation of CDI XML
files from partners databases.

In the documentation references are made to controlled lists or vocabularies, that are used
for standardised filling of a number of CDI XML tags. It has been recognised that use of
common vocabularies in all SeaDataNet metadatabases is an important prerequisite
towards consistency and interoperability. Also that it is of upmost importance that these
vocabularies are supported by a large group of stakeholders, accessable for all users and
kept up to date in a controlled way. Therefore as part of SeaDataNet work web services
have been established for Common Vocabularies and for the European Directories of
Marine Organisations (EDMO) and Marine Environmental Research Projects
(EDMERP). Also content governance has been organised for these vocabularies, EDMO
and EDMERP. The documentation gives an overview and additional information on the
web services and their content governances.




                                             6
1. Logical description of CDI metadata format
1.1 Granularity and definition

The core Common Data Index (CDI) is designed as a light metadata format, that can be
generated automatically from data centres databases, after an initial mapping exercise to
set translation properties. Each CDI should point to a data set, that can be accessed at or
delivered by the specific data centre. The CDI is instrumental for data discovery
purposes.

The definition of a dataset is arbitrary for each partner, because of the differences in
granularity that partners are applying in their archive systems for storing and accessing
datasets. A number of examples are given to illustrate the objectives and focus of the
CDI.

Case: CTD measurements
CTD casts are collected at different geographical locations, e.g. during a scientific cruise.
Each cast is represented by a data file / data set, which is stored and can be reproduced by
a data centre. The CDI record reflects the metadata of a single CTD cast, covering
multiple parameters, and including the information for accessing this specific CTD
dataset or getting a copy of this specific CTD data set. The same approach can be applied
for other in-situ and discrete measurements, such as sediment grabs, geological cores,
water bottles, etc. In each case there is an individual measurement with one instrument at
a geographical location which might have generated multiple parameters.

Case: Sea level / wave / current observations
Hydrodynamical observations are collected at different geographical locations, and might
be part of a station, equipped with a number of instruments. Each instrument produces a
timeseries of observation data, which is stored and can be reproduced by a data centre.
The CDI record reflects the metadata of the resulting dataset of a single instrument at a
single station, covering multiple parameters, and including the information for accessing
this specific dataset or getting a copy of this specific dataset. This can cover a long
timeseries. However in case there are large gaps in time coverage, the data centre might
have decided to split the data set into a sub series of data sets, each covering a consistent
observation period. In that case each sub serie is represented by a separate CDI record.

Case: Buoy with multiple sensors
In general practice a CDI will describe an observation data file from a single instrument.
However nowadays there are various instruments with multiple sensors in use, providing
their multiple parameter observations in single data files. A good example is a Poseidon
buoy or a Ferrybox, that can be equipped with a combination of sensors, while the data
are registered in a single data file. Such an observation should be described with a single
CDI record, that gives the multiple parameters, but also the multiple sensors /
instruments.




                                              7
Note: in case of an offshore platform, equipped with separate instruments for e.g. waves
and winds, that are recorded in separate data files, it is required to prepare separate CDI‟s
for each measurement!

Case: Hydrographic measurements
The bathymetry of the seabed is measured by hydrographic surveys, which cover an
specific area. Each survey can comprise a consistent timeperiod in which the area is
sampled by sailing a number of tracks, during which the seabed bathymetry is recorded in
singular tracks or zones by specific instruments. Each instrument during a specific survey
produces a hydrographic survey dataset, which is stored and can be reproduced by a data
centre. The CDI record reflects the metadata of the resulting data set of a single
instrument during a single area survey, including the information for accessing this
specific data set or getting a copy of this specific data set. The method of positioning
during the survey gives important data quality information. Therefore position systems
can be included in the CDI metadata by considering these as extra entries of the
measurement devices (= instruments). The same approach can be applied for other area
measurements, such as seismic surveys, satellite images, etc. For these types of
measurements it is also relevant to include metadata on the measurement resolution, such
as grid size or frequency.

1.2 The ISO 19115 standard

For purposes of standardisation, international exchange and interoperability with other
systems and networks it was decided to adopt the International Metadata Standard for
Geographic Information ISO 19115 as basis for the CDI format. This also fits in with the
EU INSPIRE Directive, that has adopted the ISO 19115 as its metadata standard.

The XML ISO 19115 Schema is defined and managed by the Technical committee
TC211 of the International Organization for Standardization (ISO), who is responsible for
making international standards on geographic information (www.isotc211.org). This
standard defines more than 300 metadata elements, most of which can be applied
optionally. It contains around ten elements, which are mandatory „core‟ metadata.
Moreover one can create profiles and add new elements.



                                                  Comprehensive metadata
ISO 19115 Profiles consist of :                         components
•Core +
•some/all optional +
•zero-or-more extended elements                             Core metadata
                                                              components


                                                                            Extended metadata
                                                    300+                    components
                                                    elements                (community profile)



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For the CDI V2 the ISO 19115 XML schema, delivered in annex of the FDIS ISO 19115
document, provides the basic model and is used as reference model. The CDI metadata
are constructed as a dedicated subset of this standard, which implicated an interactive
translation from the CDI metadata format into a CDI XML format, which is ISO
compliant. During this process the original CDI format was extended with a number of
fields, which are ISO mandatory, but were not planned at first instance. In addition a few
other mandatory ISO XML tags came forward, with fixed values for the SeaDataNet
domain, which are included in the CDI XML description. Guidelines were produced and
implemented on how to generate and to manage SeaDataNet XML files which handle
metadata for European Directories. These give important guidelines on several aspects,
such as management of identifiers (Identifier naming, Identifier Management, …) and
how to incorporate and code the use of Common Vocabularies, and the EDMO and
EDMERP directories in the CDI XML documents.

The CDI V2 metadata format was originally fit for describing datasets resulting from
point observations, but less suited for describing the geographical coverage of tracks and
polygons as desired for e.g. seismic and hydrographic surveys. Therefore the original
CDI V1 format and associated Schema have been extended with an GML object, which
enables to detail the geospatial features of tracks and polygons in conformity with the real
geographical coverage. Moreover it has been arranged that the CDI can include info on
multiple instruments in case of combined instruments, on positioning systems and on
resolution in space and time. Also an extension for service bindings was incorporated.
These are links (urls) to online services that allow a user or machine to get more
information on the data. Examples are a viewing service (online data viewer) or an OGC
WMS service. The current CDI V2 format allows several bindings, next to the standard
link to the central CDI portal website.

Remark:
The CDI activities started in 2005 and the CDI Schema was based upon the then
available ISO 19115 DTD. Overtime the ISO 19139 Schema has become mature and is
now part of the INSPIRE Implementing Rules as well as the Catalogue Service for the
Web – CSW ISO AP version 2.0.2 (OGC). Therefore SeaDataNet is undertaking a pilot
for implementing the CSW harvesting mechanism for metadata exchange between data
centres and portal and exploring how to upgrade the SeaDataNet metadata XML files to
the ISO 19139 schema. However full adoption of the ISO 19139 Schema will have an
impact on all tools, that SeaDataNet has developed so far for generating, editing,
exchanging and importing metadata. The technical adoption and then full uptake by all
partners will take a lot of extra efforts and time. This is therefore postponed to later
stages. But as an interim solution, SeaDataNet develops a front-end solution, that assures
that the output from the SeaDataNet portal is INSPIRE compliant. This is realized in a
cooperation with the University of Firenze (Italy) by applying their GI-CAT broker /
mediation service. GI-CAT can harmonise metadata of various resources to the ISO
19115 core profile and then produces CSW-ISO output.




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1.3 The CDI format and elements

The CDI is to give answers to the following basic questions:

      Where?
      When?
      What?
      How?
      Who?
      Where to find data?
      Station / Cruise data?
      Other relevant information?
      Other relevant services?

These basic questions are covered by specific content elements, that are detailed in the
following tables. The content elements are preceded by a CDI and data set identification,
that must be unique per data centre.

Note: Elements with their name in bold text are mandatory.




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                                  IDENTIFICATION

       FIELD                                             COMMENTS
Name by which the        Data set name, as it is uniquely known at the data centre.
data set is known
Short name of data set   Short name or acronym of the data set name. Must be unique at the data
                         centre.
CDI Local ID             Local CDI identifier at the data centre. This must be exactly the same as the
                         „Short name of data set‟ (see above). This identifier is essential for the data
                         access procedure and for the updating of CDI metadata per data centre.


                                         WHERE?

       FIELD                                             COMMENTS
Measuring area type      Point, Curve (=Track) or Surface (=Area) measurement. Supported by
                         controlled list (vocabulary L021 - SeaDataNet Geospatial Feature Types),
                         that is based upon the ISO list B.5.15 (see ISO 19115 standard). Use
                         Entrykey.
Bounding Box             Geographical coordinate (Mercator projection). Latitude of point
Latitude1                measurement or most left coordinate of bounding box in case of a curve or
                         polygon shaped surface measurement.
Bounding Box             Geographical coordinate (Mercator projection). Longitude of point
Longitude1               measurement or most lower coordinate of bounding box in case of a curve or
                         polygon shaped surface measurement.
Bounding Box             Geographical coordinate (Mercator projection). Filled in case measurement
Latitude2                data were collected along a curve or over a polygon shaped surface. Latitude
                         of most right coordinate of bounding box..
Bounding Box             Geographical coordinate (Mercator projection). Filled in case measurement
Longitude2               data were collected along a curve or over a polygon shaped surface.
                         Longitude of most upper coordinate of bounding box.
Datum Coordinate         CDI uses Geographical coordinates, preferably with Datum = WGS84. Other
system                   Datums might be used. Supported by controlled list (vocabulary L101 –
                         SeaDataNet geographic co-ordinate reference frames). Use Entrykey)
Multi Curve ID           This element including the following 4 elements can be used in case of a
                         curve measurement to detail the geographical location of the curve. The ID
                         must be a unique identifier for the curve or set of multiple curves, that are
                         described by the following 4 elements or repeated sets of these 4 elements.
Line String ID           Identifies an individual curve.
Line Description         Gives a description for an individual curve.
Line name                Gives a name for an individual curve.
Position List            Lists the geographical coordinates of the curve in sequential order. The
                         coordinates are filled in as Longitude1 Latitude1 Longitude2 Latitude2 ….
                         with the coordinates separated by spaces and not by commas. Eastern



                                                11
                      longitudes (from 0.0000 to 180.0000 (decimal [4.4]) and Northern latitudes
                      (from 0.0000 to 90.0000 (decimal [3.4]) are entered as positive and Western
                      longitudes (from 0.0000 to -180.0000 (decimal [4.4]) and Southern latitudes
                      (from 0.0000 to -90.0000 (decimal [3.4]) are entered as negative.

MultiSurface ID       This element including the following 4 elements can be used in case of a
                      polygon shaped surface measurement to detail the geographical location of
                      the surface. The ID must be a unique identifier for the surface or set of
                      multiple surfaces, that are described by the following 4 elements or repeated
                      sets of these 4 elements.
Polygon ID            Identifies an individual surface.
Polygon Description   Gives a description for an individual surface.
Polygon Name          Gives a name for an individual surface.
Pos List              Lists the geographical coordinates of the surface in sequential order. The
                      coordinates are filled in as Longitude1 Latitude1 Longitude2 Latitude2 ….
                      with the coordinates separated by spaces and not by commas. Eastern
                      longitudes (from 0.0000 to 180.0000 (decimal [4.4]) and Northern latitudes
                      (from 0.0000 to 90.0000 (decimal [3.4]) are entered as positive and Western
                      longitudes (from 0.0000 to -180.0000 (decimal [4.4]) and Southern latitudes
                      (from 0.0000 to -90.0000 (decimal [3.4]) are entered as negative.
                      The coordinate pairs should describe the polygon in a direction against the
                      clock and the first coordinate pair must be repeated as last coordinate pair!
                      Only convex polygons are to be described, which is indicated by the tag
                      <gml:exterior> .

Water depth           Water depth at location of measurement. In case of tracks or polygons can be
                      left empty or completed with an average waterdepth. Depth in metres in
                      respect to the specified vertical datum.
Vertical datum        Vertical reference of water depth. Supported by controlled list (vocabulary
                      L111 - Vertical Co-ordinate Reference System Origins). Use Entrykey)
Minimum observation   Minimum observation or data depth. The minimum instrument depth is an
depth                 acceptable approximation, if no further details are available. Depth in metres
                      in respect to the specified vertical datum.
                      If not available (unknown), use -9999.
Maximum observation   Maximum observation or data depth. The maximum instrument depth is an
depth                 acceptable approximation, if no further details are available. Depth in metres
                      in respect to the specified vertical datum.
                      If not available (unknown), use -9999.
Unit of Min and Max   Default specified as „metres‟
depth




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                                            WHEN?

        FIELD                                             COMMENTS
Start date                 Start date of the measurement data. Start and end date are noted following
                           ISO Norm 8601: YYYY-MM-DD
Start time (UT)            Start time of the measurement data. Start and end time are noted following
                           ISO Norm 8601: hh:mm:ss
End date                   End date. Filled in case of timeseries / repeated observations
End time (UT)              End time. Filled in case of timeseries / repeated observations.
Sampling Interval          Temporal resolution in case of timeseries / repeated observations. Supported
                           by controlled list (vocabulary L031 - SeaDataNet Measurement Periodicity
                           Classes) Use Entrykey.

                                            WHAT?

        FIELD                                             COMMENTS
Parameters measured        A dedicated Parameter Discovery Vocabulary (PDV) has been defined,
                           which is now maintained as a controlled vocabulary. The PDV contains a
                           hierarchical structure to support the CDI User Interface: from Discipline =>
                           Agreed Parameter Groups => BODC Parameter Groups => BODC
                           Parameter Dictionary. The CDI coding of parameters is done by including
                           BODC Parameter Group codes. These are supported by a controlled list
                           (vocabulary P021 - BODC Parameter Discovery Vocabulary) Use Entrykey.
                           Multiple codes can be entered to characterize the dataset.
Abstract                   Short description of dataset, if available. Otherwise fill in: Not specified

                                             HOW?

        FIELD                                             COMMENTS
Instrument or gear type    Supported by controlled list (vocabulary L05 - SeaDataNet device
used to collect the data   categories). Use Entrykey. Multiple codes can be entered.
and positioning system
Type of platform on        Supported by controlled list (vocabulary L061 - SeaDataNet Platform
which the sensors          Classes). Use Entrykey.
providing data for the
series were mounted
Spatial resolution or      This specifies the resolution of the measurement in time or spatial domain
frequency of               and is of particular relevance for bathymetric and seismic surveys. The
measurement                domain of resolution is indicated by „track‟ or „time‟, a numeric value and a
                           unit that is supported by controlled list (vocabulary P061 - BODC data
                           storage units). Use Entrykey.



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                                        WHO?

       FIELD                                          COMMENTS
Originator            This specifies the name, full address and profile of the organisation, that is
                      originator of the data set. It is supported by a controlled list (EDMO –
                      European Directory of Marine Organisations). Use the EDMO_code. Role
                      value is “originator”. Multiple originators can be entered.
Data Holding Centre   This specifies the name, full address and profile of the organisation, that is
                      holding the data set. It is supported by a controlled list (EDMO – European
                      Directory of Marine Organisations). Use the EDMO_code. Role value is
                      “custodian”.

                         WHERE TO FIND DATA?

       FIELD                                          COMMENTS
Data Distributor      This specifies the name, full address and profile of the organisation, that is
Centre                distributing the data set. It is supported by a controlled list (EDMO –
                      European Directory of Marine Organisations). Use the EDMO_code. Role
                      value is “distributor”.
Database reference    Identification of the database holding the dataset record at the data centre.
Data Access           Supported by controlled list (vocabulary L081 - SeaDataNet Data Access
Restrictions          Restriction Policies). Use Entrykey. Multiple entries are possible.
Function code value   A registered SeaDataNet user can use the CDI service to request retrieving
                      the identified data set by downloading. This is supported by a controlled list
                      (vocabulary L071 - SeaDataNet data access mechanisms), which is an
                      extension to ISO list B.5.3. Use Entrytermabbr. Standard and only option is:
                      „downloadRegistration‟.
Access/ordering       This specifies the URL for the SeaDataNet CDI V1 shopping and transaction
website               facility, that deals with processing shopping requests of users towards the
                      connected data centers. Standard URL is:
                      http://www.sdn-taskmanager.org/
Collating Centre =    This specifies the name, full address and profile of the organisation, that is
CDI Metadata author   the author of this CDI record. In most cases it will be the same organization
                      as the Data Distributor Centre. It is supported by a controlled list (EDMO –
                      European Directory of Marine Organisations). Use the EDMO_code. Role
                      value is “author”.




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                      CRUISE / STATION INFORMATION?

        FIELD                                             COMMENTS
                          At least cruise information or station information is mandatory. In either case
                          the 3 related fields have to be completed.
Station name              Name of measurement location. If available and relevant
Station ID                Alternative station name / number
Station Start date and    Start date and time of station observations noted following ISO Norm 8601:
time                      YYYY-MM-DDThh:mm
Cruise name               Name of cruise. If available and relevant
Cruise ID                 Alternative cruise name / number
Cruise Start Date         Start date of cruise observations noted following ISO Norm 8601: YYYY-
                          MM-DD


                      OTHER RELEVANT INFORMATION?

        FIELD                                             COMMENTS
CDI creation date         Date that the CDI metadata was created (automatic date stamp during
                          generation).
Creation / Revision       Date that the data set was created or revised.
Date /
Project name              Specifies related research projects, if relevant. It is supported by controlled
                          list (EDMERP directory – European Directory of Marine Environmental
                          Research Projects). Use the EDMERP_code. Multiple projects are possible.
Language                  Specifies language used within the dataset. Default value: en (English)
Topic Category            Main theme of the dataset. Default value: oceans
Data size                 Estimated size of the transferred data expressed in Megabytes. Can be null.
Data format               Format name of the transferred data. This is supported by a controlled list
                          (vocabulary L241 - SeaDataNet data transport formats) .Use Entrykey.
                          Multiple formats are possible.
Data Format Version       For each data format also the format version has to be given. Current
                          versions are: ODV => 0.4 ; MedAtlas => 2.0 ; CF => -99

                         OTHER RELEVANT SERVICES?

        FIELD                                             COMMENTS
                         The CDI format includes a mandatory online resource under „where to find
                         data‟ that points to the central CDI portal website and its data access
                         mechanism. Additional services might be available, such as view the data in
                         an interactive viewer, or retrieve the data using a service such as OGC WMS


                                                 15
                      or WFS. The following 4 fields enable the specification of such extra
                      services in the metadata record. Multiple sets of the 4 fields are possible to
                      describe multiple services.
Service website       This specifies the URL for the additional service.
Protocol              The protocol to be used for retrieving the information is derived from the
                      ISO 19139 definition. The contents of this element is free text, but there
                      exists a policy to format this protocol definition:
                      http://www.opengeospatial.org/ogcUrnPolicy. It is advised to follow this
                      policy.
Description           This gives a description of the extra service application.
Function code value   This is supported by a controlled list (vocabulary L071 - SeaDataNet data
                      access mechanisms), which is an extension to ISO list B.5.3. Use
                      Entrytermabbr. For additional bindings, the value could be "URL", but other
                      values from L071 are also supported.




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2.    Common Vocabularies, EDMO and EDMERP

Use of common vocabularies in all metadatabases and data formats is an important
prerequisite towards consistency and interoperability. Common vocabularies consist of
lists of standardised terms that cover a broad spectrum of disciplines of relevance to the
oceanographic and wider community. Using standardised sets of terms solves the
problem of ambiguities associated with data markup and also enables records to be
interpreted by computers. This opens up data sets to a whole world of possibilities for
computer aided manipulation, distribution and long term reuse.

Therefore common vocabularies were set-up and populated by SeaDataNet. Vocabulary
technical governance is based on the NERC DataGrid (NDG) Vocabulary Server Web
Service API. Non-programmatic access is provided to end-users by a client interface for
searching, browsing and CSV-format export of selected entries. This client interface is
online available at the SeaDataNet website in the section „Standards & Software‟. The
API is compliant to WS Basis Profile 1.1, which is adopted as standard for all Web
Services in SeaDataNet. The Voacbularies Web service is used for feeding the MIKADO
software The Vocabulary Server is populated with lists describing a wide range of
entities relevant to marine metadata and data such as parameters, sea area names, platform
classes, instrument types, and so on.

Content governance of the vocabularies is very important and is done by a combined
SeaDataNet and MarineXML Vocabulary Content Governance Group (SeaVoX),
moderated by BODC, and including experts from SeaDataNet, MMI, MOTIIVE,
JCOMMOPS and more international groups. SeaVox discussions are based on an e-mail
list server. Moreover the expansion of SeaDataNet to a wider range of ocean and marine
data types via associated projects such as e.g. Geo-Seas and the EMODNET pilots brings
forward contributions from other communities for extending the various vocabularies.

The CDI V2 format is supported by the following vocabularies.

     L021 - SeaDataNet Geospatial Feature Types

     L031 - SeaDataNet Measurement Periodicity Classes

     L05 - SeaDataNet device categories

     L061 - SeaDataNet Platform Classes

     L071 - SeaDataNet data access mechanisms

     L081 - SeaDataNet Data Access Restriction Policies

     L101 - SeaDataNet geographic co-ordinate reference frames

     L111 - Vertical Co-ordinate Reference System Origins

     L241 - SeaDataNet data transport formats


                                             17
    P021 - BODC Parameter Discovery Vocabulary

    P061 – BODC data storage units

The controlled vocabularies delivered contain the following information for each term:
    Entrykey - a compact permanent identifier for the term designed for computer
     storage rather than human readability
    Entryterm - the text string representing the term in human-readable form
    Entrytermabbr - a concise text string representing the term in human-readable form
     where space is limited
    Entrytermdef - a full description of what is meant by the term
    Entrytermlastmod – date of last modification of the term

All of the vocabularies are fully versioned and a permanent record is kept of all changes
made.

The CDI format is also supported by the following SeaDataNet European Directories
next to the Common Vocabularies:

    EDMO – European Directory of Marine Organisations

    EDMERP directory – European Directory of Marine Environmental Research
     Projects

EDMO is maintained by SeaDataNet as a central directory (European Directory of
Marine Organisations) for managing addresses and profiles of marine related
organizations. These could be research institutes, data holding centers, monitoring
organizations, and other organizations, playing a role in any of the SeaDataNet metadata
directories. EDMO is maintained by an online Content Management System, whereby
each national NODC is managing the organisation entries for its country. EDMO
provides a client User Interface for querying the database and to browse through
individual organisation profiles. This can be found at the SeaDataNet website in the
metadata section. This includes a dynamic mapping feature for locating the organisations.
EDMO also has a Web service, that is used for feeding the MIKADO software. EDMO
currently contains more than 1700 entries.

The European Directory of Marine Environmental Projects (EDMERP) gives an
overview of research projects relating to the marine environment It covers all marine
environmental disciplines. Research projects are catalogued as factsheets with their most
relevant aspects. The primary objective is to support users in identifying interesting
research activities and in connecting them to involved research managers and project
results like data, models, publications, etc. across Europe. EDMERP is maintained by an
online Content Management System or alternatively via exchange of EDMERP V1 XML
files, whereby each national NODC is managing the research project entries for its
country. EDMERP provides a client User Interface for querying the database and to
browse through individual project entries. This can be found at the SeaDataNet website in


                                            18
the metadata section. EDMERP also has a Web service, that is used for feeding the
MIKADO software. EDMERP currently contains more than 2200 entries.




                                          19
3.    How to prepare and submit CDI entries

3.1    CDI V2 Service and shopping mechanism for data access

In the SeaDataNet V2 architecture the Common Data Index (CDI) V2 metadata service
provides the link between discovery and delivery of data sets. The CDI metadata gives
users a detailed insight of the availability and geographical distribution of marine data,
archived at the connected data centres. It provides sufficient information to allow the user
to assess the data relevance.

The CDI V2 Service at the Portal provides registered users access to these distributed
data sets, managed by connected data centres. The access consists of the ability to
download data sets in common formats. This is arranged via a shopping mechanism.

At present there are 2 CDI V2 User Interfaces:
    CDI V2 – Quick Search
    CDI V2 – Extended Search

Both discovery interfaces enable users to search for data sets by a set of criteria. The
selected data sets are listed by CDI metadata records. Geographical locations are
indicated on a map. Clicking on the display icon retrieves the full CDI metadata of the
data set. This includes standardised information on the data access restrictions, that apply.
The interfaces also feature a shopping mechanism, by which selected data sets can be
included in a shopping basket.




All users can freely query and browse in the CDI V1 directory; however submitting
requests for data access via the shopping basket requires that users are registered in the
SeaDataNet Central User Register, thereby agreeing with the overall SeaDataNet User
Licence.

All data requests are forwarded automatically from the Portal to the relevant data centres.
This process is controlled via the Request Status Manager (RSM) service at the portal,
that communicates with the data centres via the Download Manager (DM) java software
module, implemented at each of the data centres.

Users receive a confirmation e-mail of their data set requests and a link to the RSM
service. By log-in to the RSM service users can check regularly the status of their


                                             20
requests and download data sets from the associated data centres, after access has been
granted. Each CDI V1 metadata record includes a data access restriction tag. It indicates
under which conditions the data set is accessable to users. Its values can vary from
„unrestricted‟ to „no access‟ with a number of values in between. During registration
every user will be qualified by its national NODC / Marine Data Centre with one or more
SeaDataNet roles. The RSM service combines for each data set request the given data
access restriction with the role(s) of the user as registered in the SeaDataNet central user
register. This determines per data set request, whether a user gets direct access
automatically, whether it first has to be considered by the data centre, that therefore might
contact the user, or that no access is given.

The following image gives an overview of the dialogue for users that use the SeaDataNet
portal. Related projects, such as Geo-Seas, Upgrade Black Sea SCENE and the
EMODNET pilots will have their own portals and CDI V1 user interfaces, but the
processing of the data requests will be handled in the same way, using the common CDI
V2 database and RSM service.




The actual delivery of data sets is done between the user and the selected data centre.
This is illustrated below for users that use the SeaDataNet portal.




                                             21
3.2       Delivery service system components

The technical configuration for the CDI V2 Service at the Portal and connected Data
Centres is illustrated in the following image.




It comprises the following components:

         CDI V2 Metadatabase and Discovery User Interface at the Portal :
          Free searching and browsing by users of metadata of data sets, managed by
          connected Data Centres. This will be in a dedicated look & feel and with a focus


                                              22
          on specific data centres and types of data per Portal (there are Portals for
          SeaDataNet, Geo-Seas, Upgrade Black Sea SCENE and the EMODNET pilots)

         SeaDataNet Central User Register - Web service:
          Containing details of users, their organizations and addresses, license period, Id-
          Passwords, and Roles, as administered by NODCs after registration submission
          by users.

         Shopping Basket – User Interface:
          Integrated in the CDI V2 user interfaces and enabling users to prepare a user
          request of multiple data sets. To submit their shopping requests users have to log-
          in with their Id-Password. The component then handles the validation of users and
          their roles via checking the Central User Register, validates the combinations of
          user role and data access restrictions (via the access decisioning matrix) and
          routes requests with their resulting access status to the Request Status Manager.

         Request Status Manager – Web service + User Interface:
          Processes and administers all requests and data deliveries (downloads), for users
          in communication with the connected data centres via their installed Download
          Manager components. Data Centres use the RSM to oversee all transactions and
          to indicate their decisions for data requests that have received the status „to be
          discussed‟ following the access decisioning matrix.

         Data Centre Download Manager – Java Tool:
          Is installed and configured at each Data Centre. It handles the communication
          with the Request Status Manager and takes care that requested files are made
          ready for downloading by User (if OK) in the agreed formats via a local website
          address at the Data Centre. The Download Manager makes use of the Coupling
          Table as a way to make a uniq link between the CDI Metadata at the Portal and
          the locally managed data files. The data files must be in one of the SeaDataNet
          exchange formats (SDN ODV4, SDN MedAtlas, SDN NetCDF (CF), ..) and can
          be in stored in a local file management system in pre-processed formats.
          Alternatively data centres can include in the Coupling Table the database queries
          to have the Download Manager retrieve and convert to SDN ODV4 format the
          requested data sets from local databases.

3.3       CDI V2 – implementation step by step

To become connected and an operational data centre in the CDI V2 service it is required
that Data Centres undertake the following implementation steps.

Step 1: Prepare CDI V2 XML test records using the SeaDataNet MIKADO software and
the latest CDI XML schema:




                                               23
MIKADO is a software tool, written in Java, which enables data centres to prepare XML
metadata files for the SeaDataNet directories EDMED, CSR, EDMERP, CDI and
EDIOS.

The latest version of the MIKADO software, including manual and training instructions,
can be freely downloaded from the SeaDataNet website (http://www.seadatanet.org) in
the section „Standards & Software‟.




Data centres can prepare XML entries manually or can generate XML entries
automatically by interfacing with local databases. MIKADO also enables data centres to
manage XML entries as a local collection. MIKADO uses the latest SeaDataNet XML
Schema‟s and makes use of the Common Vocabularies, EDMO and EDMERP
directories. The latter are each time synchronised by online connections to the respective
Web Services on user demand. For CDI MIKADO also supports the preparation of the
Coupling Table, which links the CDI metadata records and the path to retrieve the related
local data files.

In case of CDI V2 XML records, data centres are advised to produce at first a limited
number of CDI records by manual entry in MIKADO for getting better understanding of
the CDI metadata fields (see chapter 3) and the mapping to their local metadata. The
mapping comprises metadata fields, i.e. relation between local source metadata fields in a
local metadatabase and target CDI metadata fields. It also comprises semantics, i.e.
translation of local content terms to the SeaDataNet common vocabularies, EDMO and
EDMERP, specified in the CDI V2 format. Note: as part of the mapping analysis data
centres might experience missing entries in the Vocabularies, EDMO or EDMERP. If so,
then data centres are advised to contact the respective managers, i.e. BODC for the



                                            24
Vocabularies and MARIS for EDMO and EDMERP, to arrange that extensions are made
and activated.

Based upon this experience, data centres are then advised to configure MIKADO to
automatic generation of CDI V2 XML files from a local metadatabase, because in most
cases in production it concerns several thousands to hundred thousands of CDI records
for all the locally managed ocean and marine data sets.

There is functionality in MIKADO to set up and configure the connection to local
metadatabases for a range of relational DBMS and to build the related queries, using the
results of the mapping analysis.

The following image gives a manual entry page in MIKADO.




Data centres should produce again some test CDI records, but this time in automatic
mode. The CDI XML test files produced may be validated by using the SeaDataNet
XML Validation Web service that both verifies document structure and checks field
content against the Vocabulary Servers. This Validation service can be found from the
SeaDataNet website www.seadatanet.org in the section „Standards & Software‟.

If the automatic validation is OK, then data centres are advised to send these CDI test
files also to MARIS for manually checking the overall consistency and information
composition of the metadata records.



                                            25
If all is OK, then this sets the way forward for data centres to go into full production of
the CDI V2 XML files for all their locally managed ocean and marine data sets and to set
up the Download Manager software component locally. MARIS will load the received
CDI test records in the CDI V2 Test service, so that these records can be used in Step 4 to
test the installation of the Download Manager at the data centre and its communication
with the RSM at the portal.

Note: each data centre should only index data sets, that originate from institutes in their
country. That will minimize duplication of the same CDI and data sets in the central CDI
service. In case of multiple data centres in one country, there should be tuning between
these centres to prevent duplication and to establish which center submit possible
overlapping data sets. In case of international database collections, there should be
careful consideration between stakeholders how to proceed.

A Coupling Table will provide the relation between the CDI metadata files, produced
with MIKADO and locally uniquely indicated by their LOCAL_CDI_ID, and the locally
managed data sets. These data sets can be available in a local file management system as
files or in local databases, which requires queries. MIKADO has the functionality to
generate this Coupling Table during the CDI XML production, thereby distincting
between the file management system and the databases.

Extra attention should be given to the data access restriction, that the data centres want to
include for access of the data. As explained above it is practice, that users must register to
the SeaDataNet Central User Register to be able to submit requests for data access and to
download data sets, once permitted. Users only have to register once. Their request is
forwarded to their national NODC, that will validate and activate their registration as
SeaDataNet user, thereby also giving the user a SeaDataNet Role, reflecting their
affiliation (working at a governmental organisation, a research institute, etc). Users
thereafter receive an e-mail with their Id – Password. By registering to the Central User
Register users accept the SeaDataNet Data Policy and its SeaDataNet User Licence.

When users are ordering data sets via the CDI Shopping service, then their user role will
be combined with the data access restriction, included in the CDI metadata, for the
requested data sets. The combination per request is compared with the SeaDataNet
Access Decision Matrix in the RSM, that gives 3 possible outcomes:
     User will have immediate access to the data
     The User request will be considered by the Data Centre and possibly the user will
       be contacted for a negotiation
     User will be denied access

The status is administered per request in the RSM for users and data centres. The case of
immediate access is automatically processed without required intervention of the data
centre. The case of consideration requires manual intervention of the data centre.
Generally speaking data centres are advised to be not too restrictive, because that will
hamper the overall philosophy of SeaDataNet, that it is strived for full open access to data
sets. In practice it is advised to apply the restriction „SeaDataNet licence‟.


                                              26
The SeaDataNet Licence Agreement has the following terms:

1.   The Licensor grants to the Licensee a non-exclusive and non-transferable licence to
     retrieve and use data sets and products from the SeaDatanet service in accordance
     with this licence.

2.   Retrieval, by electronic download, and the use of Data Sets is free of charge, unless
     otherwise stipulated.

3.   Regardless of whether the data are quality controlled or not, SeaDataNet and the
     data source do not accept any liability for the correctness and/or appropriate
     interpretation of the data. Interpretation should follow scientific rules and is always
     the user‟s responsibility. Correct and appropriate data interpretation is solely the
     responsibility of data users.

4.   Users must acknowledge data sources. It is not ethical to publish data without
     proper attribution or co-authorship. Any person making substantial use of data must
     communicate with the data source prior to publication, and should possibly consider
     the data source(s) for co-authorship of published results.

5.   Data Users should not give to third parties any SeaDataNet data or product without
     prior consent from the source Data Centre.

6.   Data Users must respect any and all restrictions on the use or reproduction of data.
     The use or reproduction of data for commercial purpose might require prior written
     permission from the data source.

Because these terms are in conformance to national and local licence agreements as in
use by many data sources, it is encouraged that data centres and external data originators
adopt the „SeaDataNet licence‟ data access restriction as appropriate also for their data. In
practice this will imply that a registered SeaDataNet user, having accepted the overall
SeaDataNet licence agreement, can thus get access to the data sets via SeaDataNet
automatically, without any problems, via the SeaDataNet shopping services. However the
users of that data must respect the licence terms, to which they have agreed at
registration.

Another advantage of applying this data access restriction is, that the data centres do not
need to intervene for every individual data request. It is handled automatically.

Please do read the MIKADO manual and training instructions, which give additional
information on how to navigate through MIKADO, how to set up the mapping
configuration etc.

Step 2: Submit the automatically generated test CDI records to MARIS for inclusion in
the test portal



                                             27
Data centres should use MIKADO and send their automatic generated test records to the
XML Validation Services for validation: http://www.seadatanet.org/validator

If OK, then the data centres must forward the test records to MARIS for inclusion in the
CDI V2 test database, that can be queried at the following addresses:

http://seadatanet.maris2.nl/v_cdi_v2_test/search.asp
http://seadatanet.maris2.nl/v_cdi_v2_test/browse_step.asp

The test CDI database and interface are used to test out the proper installation and
configuration of the Download Manager at the data centre, by which the communication
with the RSM portal and the local data sets, in file management system or local
databases, will be arranged.

Step 3: Convert data sets to the common Data Transport Formats

As part of the V2 services, data sets are accessible via download services. Delivery of
data to users is done in common data transport formats, which interact with other
SeaDataNet standards (Vocabularies, Quality Flag Scale) and analysis & presentation
tools (ODV, DIVA). So far the following formats have been defined:
     SeaDataNet ODV4 ASCII for profiles, time series and trajectories
     SeaDataNet MedAtlas as optional extra format.
     NetCDF with CF compliance for gridded data sets

Note: it is expected that more data formats will be supported in the near future to deal
with other specific marine domains. New formats will be added to the common
vocabulary L241, so that these can be chosen for the CDI metadata, and the Data
Transport Formats documentation will be extended with new formats and their
definitions. This documentation can be found at the SeaDataNet website
www.seadatanet.org in the section „Standards & Software‟.

ODV4 and MedAtlas are ASCII formats and these have been extended with a
SeaDataNet semantic header. International cooperation is underway from SeaDataNet
together with MyOcean with the CF community, UNIDATA and the MyOcean project
for a common NetCDF format (Core Data Model – CDM) for the oceanographic and
meteorological domains, including a semantic header.

As explained in Step 1, data sets can be available at data centres in a local file
management system as files or in local databases with queries. A Coupling Table will
provide the relation between the CDI metadata files, produced with MIKADO and locally
uniquely indicated by their LOCAL_CDI_ID, and the locally managed data sets.

In case of a file management system, the format of locally held data sets might differ
from the SeaDataNet standards. Then these need to be converted, so that the files will
reside at the data centre pre-processed in the correct formats, which the Coupling Table


                                             28
will know. In case of ASCII files data centres are advised to make use of the NEMO
software tool for converting from any ASCII format to the SeaDataNet ODV4 format and
if required, also the SeaDataNet MedAtlas format. This is applicable to vertical profiles,
time-series or trajectories.

The latest version of the NEMO software, including manual and training instructions, can
be freely downloaded from the SeaDataNet website (http://www.seadatanet.org) in the
section „Standards & Software‟.




While converting NEMO can also generate the coupling table that can be used by the
Download Manager for pre-processed files from a local file management system. This is
illustrated in the image above.

Please do read the NEMO manual and training instructions, which give additional
information on how to set up the mapping configuration for NEMO etc.

It is also possible that partners write their own software for converting local files to the
SDN ODV4 format. In that case the data centres are advised to read carefully the formats
documentation and to send some sample ODV data sets to AWI for validation.

Step 4: Install and configure the Download Manager V1.1 software.

The Download Manager is a java software component, that must be installed and
configured locally at each Data Centre. It handles the communication with the Request
Status Manager (RSM) at the portal and takes care that requested files are made ready for
downloading by users (if OK) in the agreed formats via a local website address at the
Data Centre. The Download Manager makes use of the Coupling Table as a way to make


                                             29
a unique link between the CDI Metadata at the Portal and the locally managed data files.
The data files must be in one of the SeaDataNet exchange formats (see Step 3) and can be
stored in a local file management system in these pre-processed formats. Alternatively
data centres can include in the Coupling Table the database queries for the Download
Manager to retrieve data sets from local databases and to convert these to the SeaDataNet
ODV4 format for delivery to users.

Data centres are advised to contact MARIS for receiving information where to download
the package with latest version of the Download Manager software, installation and
configuration instructions and the technical documentation.

Part of the configuration is the registration of the new data centre and its Download
Manager at the RSM portal.

Data centres are advised to read and to follow up carefully the DM installation and
configuration instructions, because it is a precise activity. The well functioning of the
Download Manager installation and configuration will be tested via the CDI Test service,
which includes a test CDI database, test Shopping mechanism and test RSM. The test
system can thus be set-up as a complete system, that can be switched to operation via a
switch in the RSM configuration file. This enables also parallel functioning of the CDI
test service and CDI production service, in case of Download Manager upgrades. In that
situation the new system must be configured and tested, while the older production
version is not hampered and can stay operational for users.

The Test Request Status Manager can be found at:
http://seadatanet.maris2.nl/request/welcome_test.html

MARIS will support data centres that undertake the Download Manager installation and
configuration. The DM has several components, that can be followed and tested one by
one to achieve the required operation. First the communication set-up is tested between
the RSM and the local DM. Thereafter the full cycle is tested from discovery to request to
data download. This includes a good check on the Coupling Table which must give a
unique relation between the CDI metadata and the associated local data files or data
queries.

Please do read the Download Manager installation and configuration instructions and the
technical documentation for the full functionality. This comes with the DM software
package. Otherwise it is impossible to install and configure it properly.

Step 5: If the DM is well installed, data centres should produce a full set of CDI metadata
files, complete Coupling Table and local data sets

Using their experience gained during testing data centres are requested to produce entries
for full coverage of their locally managed data sets, comprising CDI XML files, the
Coupling Table and ODV4 files in case of a local file management system.




                                            30
Once ready, the CDI metadata should be forwarded to MARIS for inclusion in the import
version of the CDI V2 service. This can be found at:

http://seadatanet.maris2.nl/v_cdi_v2_import/search.asp
http://seadatanet.maris2.nl/v_cdi_v2_import/browse_step.asp

During import automatic checks will be applied by MARIS on the syntax (= technical
format) and semantics (=use of codes, conformity to CDI libraries, conformity to field
definitions). Validated XML files will be incorporated in the import version. Partners will
receive a report on the import, including possible rejected records and their errors.

The import version of the CDI V2 service provides a means to do a last check of the
metadata. Data centres can check the geographical distribution via the mapping
functionality and are advised to use the Summary functionality on their full results,
because that reveals very well the overall scope and consistency of the prepared
metadata.

Note: it is not possible to order data in the import version! That is only possible in the test
version and of course the production version.

Step 6: Final step: MARIS moves the production CDI V2 records to the operational CDI
V2 production system and the data centre is active.

Once the import is checked and OK and once the data centre indicates that it is ready
with its Coupling Table and files, then the data centre must request MARIS to move the
CDI records from the import to the production version of the CDI V2 service.

Therafter MARIS will set the switch at the RSM for the specific data centre to
production. From that point on the data centre will be operational and possibly receive
data requests from registered users. This will be administered in the Request Status
Manager (RSM) at the portal (see 3.1 and 3.2).

The production versions of the SeaDataNet CDI V2 user interfaces can be found at:

http://seadatanet.maris2.nl/v_cdi_v2/search.asp
http://seadatanet.maris2.nl/v_cdi_v2/browse_step.asp

Dedicated versions of the CDI user interface for related projects (Geo-Seas, Upgrade
Black Sea SCENE, and EMODNET pilots) will be operational from their respective
websites.

Step 7: Maintenance and udating




                                              31
Connected and operational data centres are requested to keep their CDI entries up-to-date
by preparing and contributing regular updates to MARIS for inclusion.

For updating the principle is that only updated XML CDI files are transferred. These can
contain new CDI entries in case of new data sets, but also modifications on existing CDI
entries or even requested deletions of existing CDI entries.

At present it is advised to data centres to undertake a regular updating, e.g. at a fixed
interval of 3 months, to contribute to an up-to-date SeaDataNet portal. It is still an
indirect process, whereby data centres take the initiative and contact MARIS for the
processing.

SeaDataNet is undertaking a pilot for implementing the OGC CSW harvesting
mechanism for metadata exchange between data centres and portal. A wider
implementation of the harvesting mechanism over all SeaDataNet partners takes lots of
efforts and is planned in the possible SeaDataNet II project, that will succeed
SeaDataNet.




                                              32
4.   References


    CDI V0 Metadata Format – documentation V3.0

    Extending CDI V1 with GML Object and Service Binding – documentation V0.4

    GML 3.1.1 Simple Features profile 1.0, 25-4-2006.
     http://portal.opengeospatial.org/files/?artifact_id=15201

    ISO 19139 draft profile for CDI 0.4.1

    MIKADO user manual

    NEMO user manual

    Guidelines for SeaDataNet XML generation - documentation 28 August 2007

    ISO 19115 Documentation - Reference number ISO 19115:2003(E)




                                             33
5.     Annexes
The document has the following annexes:

    CDI_sdn_V1.6_gml.xsd = CDI V2 Schema
    CDI_sdn_V1.6_gml.xls = Description and definition of CDI V2 tags
    CDI_sdn_V1.6_gml_ctd-example.xml = CDI V2 XML example, describing a CTD
     measurement
    CDI_sdn_V1.6_gml_multibeam-example.xml = CDI V2 XML example, describing
     a multibeam survey
    CDI_sdn_V1.6_gml_geochemical_sample-example.xml = CDI V2 XML example,
     describing a geological sample with geochemical analyses
    CDI_sdn_V1.6_gml_geological-lithology-example.xml = CDI V2 XML example,
     describing a lithological log measurement
    CDI_sdn_V1.6_gml_waves-example.xml = CDI V2 XML example, describing a
     wave timeseries measurement
    MIKADO software
    NEMO software

These annexes can be downloaded from the SeaDataNet website
http://www.seadatanet.org from the section „Standards and Software‟.




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