This is a workspace for establishing the core ISO 19115/19119 metadata needed to register air quality data access services in the GEO Clearinghouse.
Common Metadata Fields:
* File Identifier
* Metadata Link
* Digital Transfer Options/OnlineLinkage
* Responsible Party - metadadata
* Responsible party - data
* Spatial extent (bbox)
* temporal extent (Data Content Date Range)
* Service type
* Dataset Publication date
Where we are:
Three GEO Clearinghouse portals are:
Compared common fields from GEO Portal comparison to required ISO 19115. ISO 19115 is being used because it is an international standard for geographic metadata that incorporates multiple countries standards (FGDC included).
The initial metadata will be generated using the W*S GetCoverage documents, so the required fields from ISO 19115/Portals was compared to the DataFed W*S GetCoverage documents.
- Discussion on increasing GetCoverage doc to include additional metadata in order to map more completely
We created a database of the required fields for DataFed datasets: http://webapps.datafed.net/catalog.wsfl?request=wcsmetadata&datasets=AIRNOW,SURF_MET_US&format=CSV
To return all WCS datasets in one XML: http://webapps.datafed.net/catalog.wsfl?request=wcsmetadata
Where we are going:
Create core ISO 19115 metadata for W*S services through GetCapabilities (and additional user provided ISO metadata coming from semantic mediawiki?). These ISO 19115 documents will be accessed through a Web Accessible Folder (WAF). The WAF will be registered as a component in the GEOSS Registry and then the datasets registered in DataFed will be accessible through GEOSS Clearinghouse.
What are the next steps:
* access sql databast with xslt and create ISO metadata - See sample.
* create ISO 19115 metadata accessible in Web Accessible Folder
* Register WAF as component in GEOSS Registry
The Air Quality Community of Practice is creating a metadata system that allows AQ data and metadata to be harvested by the GEO and community portals through registration of OGC GetCapabilities documents for W*Ss in the AQ Community Catalog. The metadata system also allows for structured and unstructured metadata to be combined in DataSpaces, gaining additional value thorough community contributions. OGC GetCapabilities connects metadata and data.
All GEOSS data has to have a standard OGC service interface. These interfaces are described by a GetCapabilities document found on each OGC server. The GetCapabilities document is the most basic discovery metadata. This will be the core metadata in the community catalog. GetCapabilities provides the link between data access and metadata.
The Capabilities document allows machine-machine connections and points to one link for additional metadata. This metadata link would be to extended ISO 19115 standard metadata and include information about lineage and understanding the data. The ISO 19115 links back to the get capabilities. The ISO 19115 metadata can also point to other resource links, so the ISO metadata will point to the Dataspaces for the given dataset. ISO 19115 will provide structure for additional content and will connect data access and user-provided, unstructured content together.
DataSpaces is a virtual space that will combine the structured Capabilities and ISO metadata that is provided by the provider or mediator with unstructured community-provided content. This content will include discussion and feedback to the providers about the dataset, links, papers or web applications relevant to the dataset and a folksonomy of tags that provide context about the dataset that cannot be anticipated by the provider.
The first step in developing the community catalog is identifying the essential fields needed to be harvested by the GEOSS Clearinghouse GEO Portals and the GEOSS Service Registry Search and then comparing the fields that are returned
Portal Comparison: This comparison is to establish the current state of the the 3 clearinghouse portals. Identify the common fields being searched and the differences between portals and compare these fields to the OGC GetCapabilities. The outcome of this evaluation are a set of common fields that will be the initial fields used in the Air Quality Community Catalog and identification of fields found in the Capabilities document.