ICSM ISO19115-1 Metadata Best Practice Guide

Topic Category ★★★★★

Categorisation of a resource against a standardised thematic keyword list provides a useful way to filter and discover resources.

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

Definition

The main themes of the resource populated from a fixed domain of values

ISO Obligation

Discussion

The Resource Topic Category is recommended in ISO 19115.1-2015 as a metadata element to be used for discovery of geospatial resources. It provides high-level filtering of data using standardised terms from the enumeration MD_Topic CategoryCode. This enumeration cannot be extended and should not be as it is the fixed nature that makes this element of particular value. These values allow metadata aggregated from anywhere in the world to be sorted and filtered into like categories - such as is done in a faceted search interface. Search results can be easily sorted by humans and machines. If this list were extensible, this would not be as effective.

Many resources may fit into multiple categories. ISO19115-1 allows multiple instances of topicCategory to accommodate such instances. Discussions need to be made as to when an aspect of the resource is too minor to include an instance of the MD_TopicCategoryCode value.

Topic categories are essentially keywords but of a particular enumeration. Like other keywords, search engines and indices use these to provide search support. If a topic category code satisfies the need for a particular keyword, it is probably unbeneficial to include that value as part of your Keywords.

The resource to which the Topic Category applies may be data or service, MD_DataIdentification* or *SV_ServiceIdentification

ICSM Best Practice Recommendations

Therefore - in order to comply with ICSM best guidance, include at least one instance of topicCategory in the metadata for your resource to provide high-level filtering and categorisation of data. Multiple values may be captured and this is encouraged to avoid the lack of discovery due to too narrow categorisations. This field is particularly useful in faceted search interfaces such as GeoNetwork.

It is not recommended that this list be extended as its value is in part due to the standardised values it contains. Extended values, if needed are better captured in other keyword fields.

Possible Values for topicCategory

Type enumeration - MD_TopicCategoryCode

Also Consider

Crosswalk considerations

ISO19139

This element, along with spatialRepresentationType and spatialResolution, were moved from MD_DataIdentification to MD_Identification in order to allow their use for service identification. Two new values were added to this enumeration: extraTerrestrial and disaster from the ISO19139 version.

Dublin core / CKAN / data.gov.au

Maps to ISO 19115 topic

DCAT

Maps to dcat:keyword

RIF-CS

Maps to Subject

Examples

XML

<mdb:MD_Metadata>
....
  <mdb:identificationInfo>
   <mri:MD_DataIdentification>
   ....
     <mri:topicCategory>
      <mri:MD_TopicCategoryCode>environment</mri:MD_TopicCategoryCode>
     </mri:topicCategory>
     <mri:topicCategory>
      <mri:MD_TopicCategoryCode>biota</mri:MD_TopicCategoryCode>
     </mri:topicCategory>
     <mri:topicCategory>
      <mri:MD_TopicCategoryCode>inlandWaters</mri:MD_TopicCategoryCode>
     </mri:topicCategory>
     ....
   </mri:MD_DataIdentification>
  </mdb:identificationInfo>
....
</mdb:MD_Metadata>

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UML diagrams

Recommended elements highlighted in yellow

topicCategory

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