CEOS WGISS Integrated Catalog (CWIC) Douglas Nebert US Geological Survey Federal Geographic Data Committee

CEOS WGISS Integrated Catalog (CWIC) Douglas Nebert US Geological Survey Federal Geographic Data Committee

Overview Architecture of CWIC Client access to remote EO services Discussion CWIC access use case

CEOS WGISS Integrated Catalog Committee on Earth Observation Satellites (CEOS) is an inter-governmental entity to promote coordination of data and EO systems WGISS is the Work Group on Integrated Space Systems CEOS members have a diverse set of information catalogs with no common access interface CWIC was developed as a protocol gateway to provide very basic search into many partner catalogs, mapping OGC CSW search and retrieval into custom catalogs.

Architecture EuroGEOSS Discovery Broker, GENESI DEC Client, any CSW ISO AP Client CSW Client GCMD/ IDN CWIC CSW Service (Gateway) Agency-Specific Access APIs EO Collections NOAA CLASS USGS Landsat INPE NASA ECHO...

CWIC Systems Participants U.S. NOAA - Comprehensive Large Array-data Stewardship System (CLASS) U.S. NASA - Earth Observing System (EOS) Clearinghouse (ECHO) U.S. Geological Survey (USGS) - Lansdat Catalog System USGS - LSI Portal Academy of Opto-Electronics (AOE), Chinese Academy of Sciences (CAS) National Institute for Space Research (INPE), Brazil

Interactions GCMD/IDN records for CWIC assets include a collection identifier stored in the ISO metadata Keywords Query is formulated as a GetRecords request, specifying data set name via Filter expression: <ogc:propertyisequalto> <ogc:propertyname>dc:subject<ogc:propertyname> <ogc:literal>usgs:landsat_etm</ogc:literal> </ogc:propertyisequalto> Temporal and geographic query parameters are the only other filter arguments supported universally in CWIC Query is passed through to a single collection

Temporal Query Temporal extent can be specified in the CSW GetRecords request using the property name dct:coverage.datestart and dct:coverage.dateend: <dct:coverage.datestart> 2002 07 01T00:00:00Z </dct:coverage.datestart> <dct:coverage.dateend> 2002 08 01T00:00:00Z </dct:coverage.dateend> Timestamp is returned in the full record element set as elements named accordingly, similar to this: <gco:date>2011-01-01 02:15:01</gco:Date>

Spatial Query Spatial query is achieved using Filter on the BBOX envelope using geographic coordinates as follows: <ogc:bbox> <PropertyName>ows:BoundingBox</PropertyName> <gml:envelope srsname="http://www.opengis.net/gml/ srs/epsg.xml#63266405"> <gml:lowercorner>-90.0-180.0</ gml:lowercorner> <gml:uppercorner>90.0 180.0</gml:upperCorner> </gml:envelope> </ogc:bbox>

Request types GetCapabilities The mandatory GetCapabilities operation allows CWIC clients to retrieve service metadata. The response to this request shall be an XML document containing service metadata about the server. DescribeRecord The mandatory DescribeRecord operation allows CWIC clients to discover elements of the information model supported by CWIC. The operation allows some or all of the information model to be described.

Request types, continued GetRecords The mandatory GetRecords operation works as the primary mean of resource discovery in the HTTP protocal binding. It does a search and a piggybacked present. Only OGC Filter XML encoding is supported at this moment. CQL encoding is not. GetRecordById Means to acquire any individual EO data file through use of the identifier found through brief/ summary/full searches

Counting results (hits) This query is used to know the number of matched results. The response will only contains this number, and no any metadata about resources will be returned.

Brief records Used to get a number of matched record titles and links in either DC or ISO format, with the provision of paging through sets of records

Summary and Full records Typically used to get slightly more structure about records, but for CWIC catalogs, summary and full results are similar to Brief results owing to the minimal metadata managed per data resource Attributes: Identifier (used as resource ID to fetch file) Title Bounding box Date/time (in Full records)

Discussion CWIC provides access into online (not order or offline) assets by configuring a CSW proxy to multiple agency-specific As of October 2011, over 86 million individual EO data files can be found and downloaded through this system, accessing over 65 collections (data sets) GCMD/IDN records are searchable through GEOSS but do not contain strong clues for binding to the CWIC proxy and in identifying end data format Additional processing of CWIC asset descriptions in GCMD will be required for discovery of data based on data set characteristics including EO parameters and to trigger search via CWIC.

Test client Query for hit count of GOME from NOAA

Filter Query in XML

Count Results

Preferred Search Use Case for GCI Select ozone from EO vocabulary Find GOME-2 daily ozone from NOAA Formulate search based on place and time Search via CWIC to remote catalog Present results (Brief, Summary) Retrieve products through metadata link

Metadata clues in GCMD In CWIC: Dataset:

Supporting the use case EuroGEOSS Discovery Broker could be used to: Identify CWIC assets Search based on EO vocabulary Proxy the second-tier search to CWIC

Thank you Contacts: Douglas Nebert, USGS (ddnebert@usgs.gov) Martin Yapur, NOAA (martin.yapur@noaa.gov) Eugene Yu, GMU (gyu@gmu.edu)