ICSM ISO19115-1 Metadata Best Practice Guide

Parameter ★★★

Once a service operation has been discovered, potential users need to know the parameters that are required for this interface in sequence. Provision of the specifics of the operation parameters allows such evaluation and use.

   
Element Name parameter
Parent MD_Metadata.identificationInfo>SV_ServiceIdentification
Class/Type SV_Parameter
Governance Domain, Agency
Purpose Evaluation, Use
Audience machine resource - ⭑ ⭑ ⭑ ⭑
  general - ⭑ ⭑
  resource manager - ⭑ ⭑
  specialist - ⭑ ⭑ ⭑ ⭑
Metadata type structural
ICSM Level of Agreement ⭑ ⭑

Definition

the parameters that are required for a service operation interface, in sequence

ISO Requirements

This is an ISO optional element. There may be zero or many [0..*] parameter instances of class SV_Parameter associated to service operation (containsOperations, class SV_OperationMetadata) entries for the cited resource. If parameter order is important, then these should be recorded in the proper sequence.

Discussion

It is useful when documenting a service to document the particular parameters that the service operations need and expect if any. This documentation must include the parameter technical details including name, direction, optionality, and repeatability. A description of the purpose of the parameter is useful for users to evaluate the utility of such operations.

As many of the services we may call will have operations that summarise the operations that the service provides it may be better to document this one service in order not to duplicate or cause confusion. GetCapabilities would be an example of this as would an OpenAPI endpoint as implemented in OGC API common based services. These operations typically require no parameters, but the operations they describe will contain the necessary parameters.

ICSM Best Practice Recommendations

Therefore - if a potential client of a service is to use such service, descriptions of the functionality and use of the parameters required by these operations should be documented in metadata of a geospatial service. When used, this element has several mandatory subelements as described below.

SV_ParameterDirection - codelist

When describing the service parameters, the direction for each parameter must be described from the SV_ParameterDirection codelist. Available values are:

Outstanding Issues

None known

Other Discussion

None known

Crosswalk Considerations

None known

Examples

XML -

<mdb:MD_Metadata>
....
  </mdb:identificationInfo>
    </srv:SV_ServiceIdentification>
    ....
     <srv:containsOperations>
     ....
        <srv:parameter>
          <srv:SV_Parameter>
           <srv:name>
             <gco:MemberName>
              <gco:aName>
                <gco:CharacterString>VERSION</gco:CharacterString>
              </gco:aName>
              <gco:attributeType>
                <gco:TypeName>
                 <gco:aName gco:nilReason="missing">
                   <gco:CharacterString/>
                 </gco:aName>
                </gco:TypeName>
              </gco:attributeType>
             </gco:MemberName>
           </srv:name>
           <srv:direction>
             <srv:SV_ParameterDirection>in</srv:SV_ParameterDirection>
           </srv:direction>
           <srv:description>
             <gco:CharacterString>Version of WFS. Accepted value = 1.0.0</gco:CharacterString>
           </srv:description>
           <srv:optionality>
             <gco:Boolean>true</gco:Boolean>
           </srv:optionality>
           <srv:repeatability>
                <gco:Boolean>false</gco:Boolean>
              </srv:repeatability>
             </srv:SV_Parameter>
           </srv:parameter>
           <srv:parameter>
             <srv:SV_Parameter>
              <srv:name>
                <gco:MemberName>
                 <gco:aName>
                   <gco:CharacterString>REQUEST</gco:CharacterString>
                 </gco:aName>
                 <gco:attributeType>
                   <gco:TypeName>
                    <gco:aName gco:nilReason="missing">
                      <gco:CharacterString/>
                    </gco:aName>
                   </gco:TypeName>
                 </gco:attributeType>
                </gco:MemberName>
              </srv:name>
              <srv:direction>
                <srv:SV_ParameterDirection>in</srv:SV_ParameterDirection>
              </srv:direction>
              <srv:description>
                <gco:CharacterString>REQUEST=GetCapabilities</gco:CharacterString>
              </srv:description>
              <srv:optionality>
                <gco:Boolean>false</gco:Boolean>
              </srv:optionality>
              <srv:repeatability>
                <gco:Boolean>false</gco:Boolean>
              </srv:repeatability>
             </srv:SV_Parameter>
           </srv:parameter>
           <srv:parameter>
             <srv:SV_Parameter>
              <srv:name>
                <gco:MemberName>
                 <gco:aName>
                   <gco:CharacterString>SERVICE</gco:CharacterString>
                 </gco:aName>
                 <gco:attributeType>
                   <gco:TypeName>
                    <gco:aName gco:nilReason="missing">
                      <gco:CharacterString/>
                    </gco:aName>
                   </gco:TypeName>
                 </gco:attributeType>
                </gco:MemberName>
              </srv:name>
              <srv:direction>
                <srv:SV_ParameterDirection>in</srv:SV_ParameterDirection>
              </srv:direction>
              <srv:description>
                <gco:CharacterString>SERVICE=WFS</gco:CharacterString>
              </srv:description>
              <srv:optionality>
                <gco:Boolean>false</gco:Boolean>
              </srv:optionality>
              <srv:repeatability>
                <gco:Boolean>false</gco:Boolean>
              </srv:repeatability>
          </srv:SV_Parameter>
        </srv:parameter>
       </srv:SV_OperationMetadata>
     </srv:containsOperations>
    </srv:SV_ServiceIdentification>
  </mdb:identificationInfo>
....
</mdb:MD_Metadata>

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UML diagrams

{Captured from official ISO documentation at https://www.isotc211.org/hmmg/HTML/ConceptualModels/index.htm?goto=1:12:2:4095} Recommended elements highlighted in yellow

Parameter

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