Cannot BIND datatype

[Pasquale Di Donato]

Hallo list,

I'm trying to assing a data type to a value via BIND. E.g.

BIND (geo:wktLiteral(?WKT) AS ?WKT)

where geo is a PREFIX to <http://www.opengis.net/onto/geosparql#>

The data gets converted but without the data type. I get a warning:

WARN URI <http://www.opengis.net/onto/geosparql#wktLiteral> has no registered function factory.

Could you please help here?

Many thanks

Pasquale

[Richard Cyganiak]

Hi Pasquale,

What is geo:wktLiteral? It’s a datatype? In that case, you want:

    STRDT(?WKT, geo:wktLiteral)

which is how you create a typed literal for a custom datatype in SPARQL:

    https://www.w3.org/TR/sparql11-query/#func-strdt

(In systems that have GeoSPARQL support, geo:wktLiteral is probably *also* a constructor function that constructs typed literals of type geo:wktLiteral, in the same way how the XSD datatypes work as constructor functions in vanilla SPARQL. But Tarql doesn’t have GeoSPARQL support, so it doesn’t know about these constructor functions, and hence you need to create the typed literals the pedestrian way, with STRDT.)

Also I don’t think that re-binding an existing variable to a different value will work. So you probably will need to bind to a new variable:

    BIND (… AS ?WKT_typed)

Hope that helps,

Richard

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