6.1.1 Each WIS Discovery Metadata record shall validate without error against the XML schemas defined in ISO/TS 19139:2007. 6.1.2 Each WIS Discovery Metadata record shall validate without error against the rule-based constraints listed in ISO/TS 19139:2007 Annex A (Table A.1). 6.2.1 Each WIS Discovery Metadata record shall name explicitly all namespaces used within the record; use of default namespaces is prohibited. 6.3.1 Each WIS Discovery Metadata record shall declare the following XML namespace for GML: http://www.opengis.net/gml/3.2. a WIS Discovery Metadata record may declare compliance with WCMP by metadataStandardName = "WMO Core Metadata Profile of ISO 19115 (WMO Core), 2003/Cor.1:2006 (ISO 19115), 2007 (ISO/TS 19139)" (currently "") and metadataStandardVersion = "1.3" (currently ""). 8.1.1 Each WIS Discovery Metadata record shall include one gmd:MD_Metadata/gmd:fileIdentifier attribute [§8.1 ¶5] WMO Core Metadata Profile recommends the use of a URI structure for gmd:fileIdentifier attributes. Requirement 8.2.1: Each WIS Discovery Metadata record shall include at least one keyword from the WMO_CategoryCode code list. [such descriptiveKeywords must be present] Requirement 8.2.1: Each WIS Discovery Metadata record shall include at least one keyword from the WMO_CategoryCode code list. [keyword must be chosen from the list] Requirement 8.2.2: Keywords from WMO_CategoryCode code list shall be defined as keyword type “theme”. Requirement 8.2.3: All keywords sourced from a particular keyword thesaurus shall be grouped into a single instance of the MD_Keywords class. [ duplicate gmd:descriptiveKeywords instances with the same thesaurus name] It is beneficial to identify and document gmd:thesaurus for gmd:desciptiveKeywords. Requirement 8.2.4: Each WIS Discovery Metadata record describing geographic data shall include the description of at least one geographic bounding box defining the spatial extent of the data. Requirement 8.2.5: All information within a metadata record shall, as a minimum, be provided in English within the metadata record. fileIdentifier () is considered as global distribution. Requirement 9.2.1: A WIS Discovery Metadata record describing data for global exchange via the WIS shall have a gmd:MD_Metadata/gmd:fileIdentifier attribute formatted as follows (where {uid} is a unique identifier derived from the GTS bulletin or file name): urn:x-wmo:md:int.wmo.wis::{uid}. Requirement 9.1.1: A WIS Discovery Metadata record describing data for global exchange via the WIS shall indicate the scope of distribution using the keyword “GlobalExchange” of type “dataCenterdataCentre” from thesaurus WMO_DistributionScopeCode. Requirement 9.3.1: A WIS Discovery Metadata record describing data for global exchange via the WIS shall indicate the WMO Data License as Legal Constraint (type: “otherConstraints”) using one and only one term from the WMO_DataLicenseCode code list. [§9.3 ¶5] The presence of more than one WMO Data Policy statement in a single metadata record yields an ambiguous state; a WIS Discovery Metadata record describing data for global exchange shall declare only a single WMO Data Policy. Requirement 9.3.2: A WIS Discovery Metadata record describing data for global exchange via the WIS shall indicate the GTS Priority as Legal Constraint (type: “otherConstraints”) using one and only one term from the WMO_GTSProductCategoryCode code list. [§8.1 ¶9] WMO Core Metadata Profile mandates dateStamp in format YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS. [§8.1 ¶11] WMO Core Metadata Profile recommends citation date in format YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS. [§8.2 ¶3] WMO Core Metadata Profile recommends gmd:contact should use role = pointOfContact. [§8.2 ¶5] WMO Core Metadata Profile recommends email addres described in gmd:pointOfContact. [§9.1 ¶1] The scope of distribution for data within WIS shall be expressed using the following controlled vocabulary: "GlobalExchange", “RegionalExchange” and “OriginatingCentre” (if the scope of distribution is documented).