The ability to effectively exploit Earth observation and associated data resources is currently hindered by the lack of homogeneity in services and interfaces offered by the various data providers. To this end, the Catalogue Interoperability Protocol (CIP) is being developed by the Protocol Task Team within the Committee on Earth Observation Satellites (CEOS), to facilitate the access, searching and retrieval of Earth observation data.
The CEOS was set up in 1984 in response to the recommendation of a panel of satellite remote sensing experts from the Economic Summit of Industrialised Nations Working Group on Growth, Technology and Employment. It was created to provide coordination b etween all international Earth observation missions, and now encompasses all the world's civil agencies involved in Earth Observation satellite programmes. Members include ESA, NASA, DLR, NASDA, CCRS, BNSC and the CEO.
For many years now, CEOS has been working to provide short term interim standards and tools (such as the Inventory Exchange Format (IEF) and Directory Interchange Format (DIF)), whilst at the same time striving to establish long term concepts, guidelines and standards for interoperability, such as the International Interoperable Catalogue System (IICS) a nd more recently the CIP. Successful practical investigations into interoperability have been carried out by the CEOS/CINTE X task team.
The objective of the CIP is to enable the user to search many physically distributed data catalogues (without having to separately interrogate each one and manually correlate different sets of search results), effectively allowing all the data archives to appear as one database. The CIP defines the method by which data retrieval (location, requesting and delivery) is to be performed. More importantly, it defines the method of interpreting data requests, queries, and search results, and also includes th e definition of a data dictionary used to specify the common attributes that describe the primary objects within a catalogue system.
The Retrieval Manager is at the heart of the CIP. It is the software layer between the CIP user interface and a target catalogue server that facilitates the protocol functions. It operates between the client software (that supports the user in entering searches, queries and orders) and the software at the target server (that accesses the archive data) and can communicate 'invisibly' with other Retrieval Managers to accomplish this.
CIP also supports advanced concepts such as collections. These permit complex hierarchical groupings of data organised thematically over a number of physical databases, and having item descriptor members (either product descriptors or collection descri ptors).
The CEOS Protocol Task Team is the body that produces, ratifies and publishes formal CIP user requirements, protocol specification and maintenance documents. It coordinates specification of the Int eroperable Catalogue System (ICS) and Catalogue Interoperability Protocol (CIP) by collecting the requirements from CEOS Member Agencies, agreeing on the requirements, and publishing the specifications for the systems to be implemented.
The PTT is chaired by:
Gerhard Triebnig
ESA/ESRIN,
Via Galileo Galilei 1, 00044, Frascati, Italy
Tel: + 39-6-94180-535
Fax: + 39-6-94180-511
E-mail: gerhard.triebnig@esrin.esa.it
The development of the CIP has been an international collaborative effort led by the European Space Agency (ESA), NASA, and DLR with contributions from the other CEOS members. It follows and builds on the CIP-URD, a comparative analysis was performed against Z39.50 v3. The CIP Spec therefore defines a Z39.50 profile and is traceable to the CIP-URD.
The development of CIP is a 3-phased, iterative process, with ouput from one phase feeding into to the next. The three stages in its development are:
The major milestones in the CIP's 3-stage development process are summarised below:
Several agencies are currently investigating the usage of the CIP within their major programmes, such as CCRS/CEONet, ESA/MUIS, DL R/DIMS, NAS A/EOSDIS and CEO/Enabling Services.
The first-phase CIP Specification (the CIP-A Specification) was developed by Logica (UK) and ELCA (Switzerland), in conjunction with colleagues from NASA and DLR. It was formally approved by the CEOS Protocol Task Team (PPT) in March 1996. It contains an introduction to the purpose and scope of CIP, an overview of the CI P protocol, an overview of the Z39.50 facilities to be used by the CIP profile, and a definition of a CIP attribute set, tag set and database schema.
Copies of the CIP-A SPEC can be obtained by ftp from
ftp://styx.esrin.esa.it/
pub/od/CIP/cip_release_a
in both postscript and PDF format.
Within the current version of the CIP-A Spec, there are a very small number of outstanding issues which are of interest to the ZIG community, since they concern the usage of Z39.50 within the CIP. Once conerns the Data Entity Dictionary Specification Language (DEDSL) requirements for CIP that are not supported in the Z39.50 Explain database. A second issue concerns linking the UnitInfo category in the Explain database to other Explain records.
For details on these, refer to the CIP-A Spec.
A prototype kit for aspects of the CIP which investigates practically the use of Z39.50 for CIP, has been developed by Crossnet Limited for the CEO. It is based on the DBV OSI II 1.8 API d eveloped for the German Library Project, and consists of:
It features support for the Z39.50 Explain record, CIP attribute set searches, Z39.50 EXP-1 Explain attribute set searches,and the Z39.50 GRS-1 record (sufficiently to enable image transfer), and is available for SUN-OS 4.1.2 and SUN-Solaris 2.4 platf orms.
It can be obtained by anonymous ftp from;
ftp://styx.esrin.esa
/it/pub/od/CIP/software/z39cip,
ftp://sun001.sil.com/pub/z39cip
or via http://www.sil.com/computer/z
39cip.html
The CEO (Centre for Earth Observation) are now looking to build on the practical and theoretical CIP developments with the initiation of a CIP-A Demonstrator project.
The CIP-A Demonstrator is a proof-of-concept demonstrator that will provide
a test-bed for validating CIP concepts in parallel with the definition of the CIP-B
Specification, and as input to the full implementation of CIP-B. It has two main
objectives:
Furthermore, it will aid significantly in the progress of the major CEO programmes, primarily the CEO Enabling Services.
The CIP-A Demonstrator implementation team comprises Logica, DLR, and Joanneum Research.
The Demonstrator will comprise a Z39.50 client and server with a WWW front-end and a CIP Retrieval Manager as client/server middleware. The project will integrate existing catalogues including catalogues from DLR and Eumetsat.
The Demonstrator documents and software should be available to the user community towards the end of 1996.
For more information on the CIP-A Demonstrator, contact the CEO team:
Peter Churchill
CEO Project Manager,
Joint Research Centre,
1-21020, Ispra (Va), Italy.
Tel: +39-332-785031
Fax: +39-332-785031
E-mail: peter.churchill@jrc.it
Alternatively, contact:
Stuart Mills
Logica UK Ltd,
Wyndham Court,
74 Portsmouth Road, Cobham, Surrey, KT11 1HY, UK.
Tel: +44-171-446-4416
Fax: +44-1932-869112
E-mail: millss@logica.com