SeaDataNet > Data Access > Common Data Index (CDI)
Common Data Index (CDI)
The Common Data Index (CDI) service gives users a highly detailed insight in the availability and geographical spreading of marine data sets, that are managed by the SeaDataNet data centres. Moreover it provides a unique interface for requesting access, and if granted, for downloading data sets from the distributed data centres across Europe.
The CDI Version 1 has been launched as pilot in 2008 and very good progress is being made with its population by all SeaDataNet data centres. The aim is to achieve a complete coverage by end 2009. For upgrading from CDI V0 to V1, the CDI metadata format has been upgraded, harmonising it with the other SeaDataNet directories. Moreover a major functionality has been added: by means of a data shopping, tracking and download service mechanism users are provided with a unique and harmonised access to the data sets, that are managed at the distributed data centres. Furthermore, the data sets are delivered by all data centres in standard SeaDataNet data transport formats.
- Query the Common Data Index (CDI) V1 (meta)data access service - Quick Search
- Query the Common Data Index (CDI) V1 (meta)data access service - Extended Search
Note: registration in the SeaDataNet User Register is required for submitting data requests and downloading!
How does it work?
The process from search to getting access to requested data sets is illustrated and explained below. This allows users to retrieve data sets from distributed data centres in a common way via one unique portal.
The CDI V1 query interface enables to search by a set of criteria. The selected data sets are listed. Geographical locations are indicated on a map. Clicking on the display icon retrieves the full metadata of the data set. This gives information on the what, where, when, how, and who of the data set. It also gives standardised information on the data access restrictions, that apply. The interface features 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 SeaDataNet 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. 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 requests and download data sets from the associated data centres, after access has been granted. On their turn, data centres can follow via the RSM service all transactions for their data sets online and can handle requests which might require their mediation.
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.
Earlier CDI V0
The CDI Version 0 has been operational since 2007 and populated by nearly all SeaDataNet data centres. It gives a unified index to the data sets, that are managed by the data centres. However for data access, users are pointed in the CDI metadata towards the websites or data request systems of individual centres. It contains more than 340.000 individual data entries, covering a broad scope and range of data, held by SeaDataNet data centres. However it is no longer maintained, because the focus is on rolling out and maintaining the CDI V1 service. It will be phased out and deleted from the public services, once all SeaDataNet data centres are included in CDI V1.