Copyright © 2010 Open Geospatial Consortium
59 9.4 Exceptions
In the event that a web feature service encounters an error parsing a DescribeFeatureType request, it shall raise an OperationParsingFailed exception as described in 7.5.
In the event that a web feature service encounters an error processing a DescribeFeatureType request, it shall raise an OperationProcessingFailed exception as described in 7.5.
10 GetPropertyValue operation
10.1 Introduction
The GetPropertyValue operation allows the value of a feature property or part of the value of a complex feature property to be retrieved from the data store for a set of features identified using a query expression
see 7.9.
10.2 Request 10.2.1 Request Semantics
Figure 15 describes the schema of a GetPropertyValue request.
BaseRequest + service : CharacterString = WFS {frozen}
+ version : CharacterString = 2. 0.0 {frozen} + handle [0..1] : CharacterString
GetPropertyValue + query : QueryE xpression
+ valueReference : ValueReference ResolveValue
+ local + remote
+ all + none
Enumeration {resolveDepth0 implies
resolvenone and resolveTimeout-notEmpty
implies resolvenone}
ResultType + results
+ hits Enumeration
StandardResolveParameters + resolve : ResolveValue = none
+ resolveDepth : UnlimitedInteger = isInfinite + resolveTimeout : TM_Duration = 300s
StandardPresentationParameters + resultType : ResultType = results
+ outputFormat : CharacterString = textxml; subty pe=gml 3... + count [0..1] : Integer
+ startIndex : Integer = 0 ResolveWithPath
+ resolvePath [0..1] : CharacterString
{query.oclIsTypeOfAdhocQuery or query. oclIsTypeOfStoredQuery}
Figure 15 — GetPropertyValue request 10.2.2 XML Encoding
The following XML fragment defines the XML encoding for the GetPropertyValue operation:
xsd:element name=GetPropertyValue type=wfs:GetPropertyValueType xsd:complexType name=GetPropertyValueType
xsd:complexContent xsd:extension base=wfs:BaseRequestType
xsd:sequence xsd:element ref=fes:AbstractQueryExpression
xsd:sequence
60
Copyright © 2010 Open Geospatial Consortium xsd:attribute name=valueReference type=xsd:string use=required
xsd:attribute name=resolvePath type=xsd:string xsd:attributeGroup ref=wfs:StandardPresentationParameters
xsd:attributeGroup ref=wfs:StandardResolveParameters xsd:extension
xsd:complexContent xsd:complexType
10.2.3 KVP Encoding
Table 16 defines the KVP encoding for the GetPropertyValue operation.
Table 16 — Keywords for GetPropertyValue KVP encoding
URL Component OMa
Description
Common Keywords REQUEST=GetPropertyValue
See Table 7. Only keywords listed for all operation or the GetPropertyValue
operation. Adhoc Query Keywords
Mutually exclusive with Stored Query Keywords
See Table 8. Stored Query Keywords
Mutually exclusive with Adhoc Query Keywords
See Table 10. VALUEREFERENCE M
See 10.2.4.3.
RESOLVEPATH O See
7.9.2.4.7. a
O = Optional, M = Mandatory
10.2.4 Parameter discussion 10.2.4.1 Standard presentation parameters
See 7.6.3.
10.2.4.2 Standard resolve parameters
See 7.6.4.
10.2.4.3 valueReference parameter
The valueReference parameter is an XPath expression see ISO 19143:2010, 7.4.4 that identifies a node, or child node of a property node of a feature whose value shall be retrieved from a servers data store and
reported in the response document.
The response shall be a text node or a list of element nodes that is the value of the node pointed to by the valueReference parameter.
In the case where the value is a reference to a remote resource, the valueOf accessor function may be used to resolve the remote value.
NOTE There is a difference between how the valueReference parameter with the valueOf XPath operator see
7.3.2 behaves and what the standard resolve parameters control. The valueReference is used to express queries to determine the featuresvalues in the result set while the standard resolve parameters see 7.6.4 are used to determine
how property values inside the selected featuresvalues are encoded and presented in response documents.
EXAMPLE Consider the following XML fragment encoding an instances of the feature type myns:Person:
