Data Access service - CDI
For the data access system CASPINFO makes use of SeaDataNets CDI techniques and formats.
The Common Data Index (CDI) was initiated in the Sea-Search project. As part of SeaDataNet it is being further developed and extended in data coverage to all SeaDataNet data centres and it is now also used in the Black Sea satellite project (Upgrade) BlackSeaScene, and in the CASPINFO project. Its primary objective is to give users a highly detailed insight in the availability and geographical spread of marine data across the different data centres and institutes across Europe. The CDI provides an index (metadatabase) to individual data sets. Furthermore it provides direct online data access or direct online requests for data access or file downloads.
In the CASPINFO project only the first steps in actual data access have been made. The aim has been more to analyse and inform/train the partners on the basics of the possibilities. But still, a prototype has been achieved! The CASPINFO CDI V3 metadatabase contains a first set of individual data entries from only a few Data Holding Centres from the countries around the Caspian Sea.
The CDI metadirectory can be queried and entries can be viewed by users. A versatile user interface, combining alphanumeric search criteria with a dynamic mapping tool, is available for users to specify their query requirements. The resulting entries matching the query are presented in a dynamic map and a browse list. This list allows for sorting on a number of key fields. Additional details per entry can be viewed by clicking on a Show button or by clicking on items on the map. The viewer includes a full screen presentation of each CDI entry. The names of the organisations involved are listed with hyperlinks, which provide the full address and profile description of the specific organisation. A special section of the CDI presentation lists details on the access restrictions of the data set. Data sets can be ordered by collecting them in the shopping basket and after that logging in (one time registration to SeaDataNet is needed) and then download them, if the access restrictions allow this.
For more information on the full procedure of CDI V3 please check this page http://www.seadatanet.org/Data-Access
Maintenance of CDI and formats
For purposes of standardisation and international exchange the ISO19115 metadata standard has been adopted. The CDI format is defined as a dedicated subset of this standard and ISO compliant. A CDI XML format supports the exchange between CDI-partners and the central CDI manager, and ensures interoperability with other systems and networks. CDI XML entries are generated by participating data centres (i.e. CDI-partners), directly from their databases. CDI-partners can make use of a dedicated Java Tool - MIKADO - to generate CDI XML files automatically, following a properties file, which defines the mapping between CDI-format and partner's database fields and the required local queries. CDI updates are produced and transferred at regular intervals. Full documentation on the CDI format, MIKADO Tool and supporting lists can be found at: http://www.seadatanet.org.
Apart from that, all datasets collected via the system are provided in the same fileformat: ODV for data profiles, NetCDF-CF for gridded data. This means that the datasets can easily be used in teh ODV software, which is also available via the SeaDataNet website.