metadataURL in Layer WMS

[trodin]

Question about MatadataURL element in Layer element in the WMS Capabilities document: There should be exactly one MetadataURL per layer or is it possible to have more than one MetadataURL inside one Layer element?

Thank you,
Tanja

[trodin]

I mean this for child layer. One child layer element- one metadataURL?

[heidivanparys]

Short answer: yes, it is possible to have more than one MetadataURL inside one Layer element.

Long answer:

From the WMS specification:

<element name="Layer">
<annotation>
<documentation>
Nested list of zero or more map Layers offered by this server.
</documentation>
</annotation>
<complexType>
<sequence>
<element ref="wms:Name" minOccurs="0"/>
<element ref="wms:Title"/>
<element ref="wms:Abstract" minOccurs="0"/>
<element ref="wms:KeywordList" minOccurs="0"/>
<element ref="wms:CRS" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:EX_GeographicBoundingBox" minOccurs="0"/>
<element ref="wms:BoundingBox" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:Dimension" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:Attribution" minOccurs="0"/>
<element ref="wms:AuthorityURL" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:Identifier" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:MetadataURL" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:DataURL" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:FeatureListURL" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:Style" minOccurs="0" maxOccurs="unbounded"/>
<element ref="wms:MinScaleDenominator" minOccurs="0"/>
<element ref="wms:MaxScaleDenominator" minOccurs="0"/>
<element ref="wms:Layer" minOccurs="0" maxOccurs="unbounded"/>
</sequence>
<attribute name="queryable" type="boolean" default="0"/>
<attribute name="cascaded" type="nonNegativeInteger"/>
<attribute name="opaque" type="boolean" default="0"/>
<attribute name="noSubsets" type="boolean" default="0"/>
<attribute name="fixedWidth" type="nonNegativeInteger"/>
<attribute name="fixedHeight" type="nonNegativeInteger"/>
</complexType>
</element>

(note the maxOccurs="unbounded" for wms:MetadataURL)

and

<element name="MetadataURL">
<annotation>
<documentation>
A Map Server may use zero or more MetadataURL elements to offer
detailed, standardized metadata about the data underneath a
particular layer. The type attribute indicates the standard to which
the metadata complies. The format element indicates how the metadata is structured.
</documentation>
</annotation>
<complexType>
<sequence>
<element ref="wms:Format"/>
<element ref="wms:OnlineResource"/>
</sequence>
<attribute name="type" type="NMTOKEN" use="required" />
</complexType>
</element>

From https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:02008R1205-20081224#tocId18:

If the resource is a spatial data service, this metadata element identifies, where relevant, the target spatial data set(s) of the service through their unique resource identifiers (URI).

Note the plural: spatial data set(s).

From https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:02008R1205-20081224#tocId50:

| 1.6 | Coupled resource | 0..* | Mandatory if linkage to data sets on which the service operates are available. |

Again, plural: 0..*

(the "Coupled resource" is expressed in the MetadataURL: see the TG on view services:

)

[heidivanparys]

@trodin I hope that the answer provided has helped you. I'll close the issue, but feel free to re-open it in case you have additional questions.