Core metadata for OWS 2

6.3 Core metadata for OWS 2

Table 2 shows a more complete list of core metadata elements, in particular those that are relevant to OWS 2. This clause is a discussion of that list. Discussion already in clause 6.2 and relevant only to the mandatory core elements is not repeated. While the presence of these metadata elements is optional, they must be used in the way prescribed in 19115 if they are present. There is a new column for Obligation Obl., which tells whether the element is mandatory M, optional O, or mandatory only under certain electronically manageable conditions. Some of the elements in classes that are optional are listed as mandatory or conditional. A mandatory listing for such an element means that the element must be present if the class is present; a conditional listing means that the element must be present if the class is present and the conditions are satisfied. The elements are not globally mandatory. If the class of which they are a member is absent, they will be absent. If a class is absent, perhaps in the context of being the data type of an optional element, then its subclasses, aggregation components, and their elements should not be present with blank values or values such as “not available” or “unknown”. Not all elements in optional classes of core metadata are themselves part of the core metadata. The table does not specifically list all such elements. Generally, when such elements exist but are not specifically listed, there is a note in the table to that effect. Annex E.2 of ISO 19139 provides an XML instance document including all the core metadata elements. The metadata standard name should be the universally recognized name of the metadata standard, such as ISO 19115 or the FGDC Content Standard for Digital Geospatial Metadata, not some local name given to the standard. Similarly, the version should not be a local designation but a universally recognized name such as that of a profile. Note that there is separate contact information for the data and metadata. The metadata contact is a required element and identifies the party responsible for the metadata. The point of contact that is part of MD_Identification identifies the entity associated with data and provides contact information. The roles may be different. The metadata contact might be the resource provider, custodian, or distributor. The data contact might be the originator or the principal investigator. Vertical extent information is optional, but if it is present, both the maximum and minimum value must be provided. Similarly, temporal extent information is optional. This metadata element refers to ISO 19108. The temporal extent must be one of two subtypes. It may be a TM_Instant, a specific moment, either an exact time given by date, time, or both, or an indefinite time defined by its occurrence relative to another time. It may be instead a TM_Period, an interval with a beginning and an end. The reference system can be furnished in one of two ways. The metadata may provide the projection, ellipsoid and datum. If it does not do so, then a code to identify the 10 © Open Geospatial Consortium 2005 Table 2 — Expanded core metadata elements Class ISO element Value Obl. Remarks MD_Metadata language C For metadata, required if not defined by the encoding characterSet C For metadata, required if neither ISOIEC 10646-1 nor defined by encoding dateStamp M Metadata creation date in ISO 8601 format fileIdentifier O metadataStand ardName O Name of Metadata standard used; e.g., ISO 19115 metadataStand ardVersion O Of the standard in the metadataStandardNam eElement contact:CI_ResponsibleParty Contact for metadata organisationin dividualpositi onName M role M owner, originator, etc. MD_Identification abstract M pointOfContact:CI_ResponsibleParty O Contact for data organisationin dividualpositi onName M role M owner, originator, etc. citation:CI_Citation title M date:CI_Date date M dateType M creation, revision, etc. MD_DataIdentification spatialReprese ntationType O grid, textTable, video, etc. language M For data characterSet C For data, required if ISOIEC 10646-1is not used topicCategory M elevation, environment, inlandWaters, etc. spatialResolution:MD_Resolution O Either equivalentScale or distance must be present distance C equivalentScale:MD_Representati veFraction C denominator M © Open Geospatial Consortium 2005 11 Class ISO element Value Obl. Remarks extent:EX_Extent M Required for a datasetgranule MD_Metadata.hierarc hyLevel=dataset EX_GeographicExtent M Either EX_GeographicBound ingBox or EX_GeographicDescri ption must be present EX_GeographicBoundingBox C westBoundLon gitude M eastBoundLon gitude M southBoundLa titude M northBoundLat itude M EX_GeographicDescription C geographicIdentifier:MD_Ide ntifier M code M a character string codespace O a character string EX_VerticalExtent O minimumValu e M maximumValu e M EX_TemporalExtent O extent:TM_Primitive M ISO 19108; abstract, one or more of two subclasses is instantiated TM_GeometricPrimitive abstract, one or more of two subclasses is instantiated TM_Instant position:TM_Position Union: one of four elements is present date8601 C time8601 C dateTime8601 C anyother:TM_Temporal Position C indeterminateP osition O unknown, now, before, or after TM_Period TM_Instant O two instances: beginning and end DQ_DataQuality O LI_Lineage O LI_Source O all elements optional LI_ProcessStep O 12 © Open Geospatial Consortium 2005 Class ISO element Value Obl. Remarks description M additional optional elements MD_ReferenceSystem O referenceSystemIdentifier:RS_Identifier C required if projection, ellipsoid and datum from MD_CRS are not present code M inherited from MD_Identifier codeSpace O inherited from MD_Identifier, a character string version O authority:CI_Citation O MD_CRS O projection O ellipsoid O datum O MD_Distribution O MD_Format C Required if MD_Distributor.distri butorFormat not documented name M version M MD_DigitalTranferOptions O All elements optional, describe size and how available unitsOfDistrib ution O Tiles, layers, geographic areas in which data is available transferSize O Size, in megabytes, of a unit of the transport format used online:CI_OnLineResource O linkage M URL protocol O Connection protocol applicationPro file name description function e.g., download, search, order offline:MD_Medium name e.g., CD-ROM, DVD, 3.5-inch floppy, hardcopy density densityUnits volumes mediumForma t e.g., CPIO, tar, ISO 9660 mediumNote © Open Geospatial Consortium 2005 13 coordinate system must be provided. Providing the code space in which the coordinate system is defined will help the user to identify the coordinate system corresponding to the code. The core distribution metadata is the format. In the 19115 standard, it may be provided along with the distributor contact information or separately. The distributor contact information is not core metadata. 7 OWS 2 metadata examples

7.1 Introduction