ICSM ISO19115-1 Metadata Best Practice Guide

Temporal Extents ★★★

To quickly determine the temporal range of features included in an identified resource it is useful that the extent information include any temporal extents and limitations.

   
Element Name temporalElement
Parent MD_Metadata.identificationInfo>MD_Identification.extent
Class/Type EX_TemporalExtent
Governance Common ICSM, Domain
Purpose Discovery
Audience machine resource - ⭑ ⭑ ⭑ ⭑
  general - ⭑ ⭑ ⭑ ⭑
  resource manager - ⭑ ⭑
  specialist - ⭑ ⭑ ⭑
Metadata type descriptive
ICSM Level of Agreement ⭑ ⭑ ⭑

Definition

This element provides a temporal component of the extent of the resource to aid discovery.

ISO Obligation

Discussion

Every metadata record describing resources should describe the temporal validity of the resource.

The use of multiple temporal extents is useful for describing more complicated resources. Where these are tied to and vary by spatial dimensions in the resource these may be expressed using EX_SpatialTemporalExtent.

With the advent of dynamic datums for high precision applications of spatial data, temporal information becomes even more important.

ICSM Best Practice Recommendations

Therefore - it is strongly recommended that to support discovery of resources, and ensure the resource is fit to purpose, every metadata record contains, as needed, temporal extent description of the resource period of interest. Dates may be captured as type date or datetTime depending on your need and tools. If your data is of high precision then capture temporal extents to support dynamic datums. the capture of timePeriod information is highly recommended.

The MDWG recommends populating as many instances of temporalExtent packages as needed to give a common understanding of the temporal coverage of the cited resource.

## Also Consider

## Outstanding Issues

Our understanding of temporal metadata is poor and the documentation of such is weak and by reference in ISO19115-1. There is the use of GML elements when these are described as being TM_Primitives. What is the relation? Also, What about Time node and Time edge? Need help with this timey whimey stuff.

Crosswalk considerations

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

Mapping 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="d5078594e414a1056030">
              <gml:begin>
               <gml:TimeInstant gml:id="d5078594e416a1056030">
                 <gml:timePosition>2019-07-01</gml:timePosition>
               </gml:TimeInstant>
              </gml:begin>
              <gml:end>
               <gml:TimeInstant gml:id="d5078594e420a1056030">
                 <gml:timePosition>2019-07-31</gml:timePosition>
               </gml:TimeInstant>
              </gml:end>
            </gml:TimePeriod>
           </gex:extent>
         </gex:EX_TemporalExtent>
        </gex:temporalElement>
      </gex:EX_Extent>
     </mri:extent>
   ....
   </mri:MD_DataIdentification>
  </mdb:identificationInfo>
....
</mdb:MD_Metadata>

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UML diagrams

Recommended elements highlighted in yellow

temporalExtent

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