Copyright © 2014 Open Geospatial Consortium
25 The optional strength parameter is used to indicate a matching threshold beyond which
the PropertyMatches operator shall evaluate to true. The value of strength parameter shall be a value between 1 and 100 with 100 indicating that the arguments must be
identical in order for the PropertyMatches operator evaluates to true. Lower values allow for increasingly “fuzzier” matches.
Example: The following example searches for alternative geographic identifiers that are a 90 match for the string “Albeon” using the Jaro-Winkler algorithm.
ogc:PropertyMatches method=jaro-winkler ogc:PropertyNamealternativeGeographicIdentifierogc:PropertyName
ogc:MatchString strength=”90”Albeonogc:MatchString ogc:PropertyMatches
This predicate would, for example, match the string Ablion. The successful use of the PropertyMatches operator confirmed its utility and potential
role in future WFS-G usage. It is therefore recommended that this operator be included in future revisions of OGC standards.
8.3 Query by Feature Description
8.3.1.1 Introduction
The user should be able to filter queries by the feature description also known as the feature designation. This description could reflect the terminology of either agency, i.e.,
the user should be able to query on USGS feature descriptions or NGA feature designations. These should be expanded to common language descriptions rather than
codes. As an example, a user should be able to select USGS feature descriptions and pick a term like ‘summit.’ This term would access information from related NGA feature
classes, such as ‘mountain’, ‘hill’, ‘peak’, ‘rock’, etc. The user should also be able to filter features based on the use of NGA terms. In this case, picking a term like ‘hill’
would return USGS ‘summit’ features. These mappings should be displayed to the user on the query form.
For the demo scenario the delegation would look for a town, i.e. a populated place. The selection in the client thus applies a source gazetteer description filter, narrowing the
query down to features complying to the following NGA LocationTypes:
PPL, PPLA, PPLA2, PPLA3, PPLA4, PPLC, PPLF, PPLH, PPLL, PPLQ, PPLR, PPLS, PPLW,PPLX, STLMT
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8.3.1.2 XML encoding
The PropertyIsSemanticallyRelatedTo operator, proposed in OWS-9, was reused for Testbed-10. A minor modification was made in constraining queries by placetype rather
than URI. This modification was made because the URIs hyperlinks in SI_LocationType instances used in Testbed-10 were found to be different from those used OWS-9; the
placetypes however remain the same between different implementations.
ogc:PropertyIsSemanticallyRelatedTo ogc:PropertyNameiso19112:locationTypexlink:titleogc:PropertyName
ogc:Literallocaleogc:Literal ogc:PropertyIsSemanticallyRelatedTo
8.3.1.3 KVP encoding
The PropertyIsSemanticallyRelatedTo operator is used within the Filter submitted with the request.
8.3.1.4 Parameter discussion
The PropertyIsSemanticallyRelatedTo operator, as used in Testbed-10, accepts only two parameters an XPath through the PropertyName parameter and a locationType name
through Literal property.
8.4 Query by Country
