ICSM ISO19115-1 Metadata Best Practice Guide

Extent Geographic Description ★★★★

To quickly determine the general location of spatial features included in a cited resource, it is useful that the extent information contains a verbal description of the geographic extent using common (to your community) place names.

   
Element Name geographicIdentifier
Parent MD_Metadata.identificationInfo>MD_Identificationextent >EX_Extent.geographicElement>
Class/Type EX_GeographicDescription
Governance Common ICSM, Domain
Purpose Discovery
Audience machine resource - ⭑ ⭑ ⭑
  general - ⭑ ⭑ ⭑ ⭑
  resource manager - ⭑ ⭑
  specialist - ⭑ ⭑ ⭑ (higher if domain specific placenames are used)
Metadata type descriptive
ICSM Level of Agreement ⭑ ⭑ ⭑

Definition

A Geographic description or placename which describes the location of the resource.

ISO Obligation

Discussion

To provide a quick guide as to the spatial area of interest for a cited resource, every metadata record describing geographic resources should contain a descriptor that indicates the location of the area of interest of the resource. Catalogue software can use this information to analyse and narrow searches to particular areas of interest.

The use of multiple descriptors is recommended for more complicated geometries, including exclusion areas.

ICSM Best Practice Recommendations

Therefore - it is highly recommended that to support the discovery of resources, every metadata record that describes a geographic resource contains geographic descriptions of the area of interest for the resource. This description must contain a code that holds the value of the geographic descriptor and should contain in the codespace the codelist or domain from which it was derived. The authority element may contain additional documentation of the codelist.

The MDWG recommends including as many instances of Geographical Extent packages as useful to give a common understanding of the spatial coverage of the cited resource. These names may be particular to your domain.

Use extentTypeCode (type - Boolean) [0..1] with a value of “0” to indicate exclusions class MD_Identifier

Also Consider

Outstanding Issues

GeoNetwork use of EX_Extent.description The “description” element of EX_Extent offers a freeform way of describing the extent of a resource. GeoNetwork uses it to provide a codelist delimited set of values by which the EX_GeographicBoundingBox elements are populated. It would seem more correct to use EX_GeographicDescription and its MD_Identifier element to this purpose.

Crosswalk considerations

Dublin core / CKAN / data.gov.au {if any}

Mapping geographic extents to CKAN and Dublin core elements, particularly as used by data.gov.au needs discussion

Examples

XML

<mdb:MD_Metadata>
....
  <mdb:identificationInfo>
   <mri:MD_DataIdentification>
   ....
     <mri:extent>
      <gex:EX_Extent>
        <gex:temporalElement>
         <gex:EX_TemporalExtent>
           <gex:extent>
            <gml:TimePeriod gml:id="A1234">
              <gml:beginPosition/>
              <gml:endPosition/>
            </gml:TimePeriod>
           </gex:extent>
         </gex:EX_TemporalExtent>
        </gex:temporalElement>
      </gex:EX_Extent>
     </mri:extent>
     <mri:extent>
      <gex:EX_Extent>
        <gex:geographicElement>
         <gex:EX_GeographicBoundingBox>
           <gex:westBoundLongitude>
            <gco:Decimal>110.70922852</gco:Decimal>
           </gex:westBoundLongitude>
           <gex:eastBoundLongitude>
            <gco:Decimal>157.79663086</gco:Decimal>
           </gex:eastBoundLongitude>
           <gex:southBoundLatitude>
            <gco:Decimal>-39.32048764</gco:Decimal>
           </gex:southBoundLatitude>
           <gex:northBoundLatitude>
            <gco:Decimal>-10.68489957</gco:Decimal>
           </gex:northBoundLatitude>
         </gex:EX_GeographicBoundingBox>
        </gex:geographicElement>
        <gex:geographicElement>
         <gex:EX_GeographicDescription>
           <gex:geographicIdentifier>
            <mcc:MD_Identifier>
              <mcc:code>
               <gco:CharacterString>
               Australia
               </gco:CharacterString>
              </mcc:code>
            </mcc:MD_Identifier>
           </gex:geographicIdentifier>
         </gex:EX_GeographicDescription>
        </gex:geographicElement>
      </gex:EX_Extent>
     </mri:extent>
   ....
   </mri:MD_DataIdentification>
  </mdb:identificationInfo>
....
</mdb:MD_Metadata>

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UML diagrams

Recommended elements highlighted in yellow

ExGeoDescription

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