Geometry encoding as Schema.org

[dr-shorthair]

Add asSchemaDotOrg (datatype property) and schemaLiteral (datatype) to support popular geometry encoding

https://schema.org/GeoShape --> polygon
https://schema.org/Place --> (latitude, longitude)

[dr-shorthair]

Note: this is already on the agenda for OGC GeoSPARQL revision, so we can test it more rapidly here.

[nicholascar]

Property:

:asSchemaDotOrg 
    a owl:DatatypeProperty ;
    rdfs:subPropertyOf :hasSerialization ;
    rdfs:domain :Geometry ;
    rdfs:range :schemaLiteral ;
    dcterms:date "2020-06-04"^^xsd:date ;
    rdfs:isDefinedBy <http://linked.data.gov.au/def/geox> ;
    skos:definition """The Schema.org serialization of a geometry"""@en ;
    skos:prefLabel "as schema.org"@en ;
.

Literal:

:wktLiteral 
    a rdfs:Datatype ;
    dcterms:date "2020-06-04"^^xsd:date ;
    rdfs:isDefinedBy <http://linked.data.gov.au/def/geox> ;
    skos:definition "A schema.org Text serialization of a geometry object."@en ;
    skos:prefLabel "schema.org Literal"@en .

So the property's easy. I guess it's the microformat of the Literal that I need to understand. The notes from https://schema.org/GeoShape regarding the microformat are:

A polygon is the area enclosed by a point-to-point path for which the starting and ending points are the same. A polygon is expressed as a series of four or more space delimited points where the first and final points are identical.

Is this sufficient? WGS84 is presumed.

What about the schema.org and other ontology's ways of expressing geometry with a Point-like object: schema:GeoCoordinates for example:

GeoCoordinates:
https://schema.org/longitude
https://schema.org/longitude
https://schema.org/elevation

[dr-shorthair]

The other gotcha is how to escape JSON syntax elements within the RDF literal. Didn't we see this somewhere already?

[dr-shorthair]

It looks like the datatype for a JSON literal is just rdf:JSON (or possibly a sub-type) as described here https://w3c.github.io/json-ld-syntax/#the-rdf-json-datatype

It is in the RDF syntax doc here https://www.w3.org/1999/02/22-rdf-syntax-ns# but is not described in the RDF syntax rec.

Strings MUST be serialized with Unicode codepoints from U+0000 through U+001F using lower case hexadecimal Unicode notation (\uhhhh) unless in the set of predefined JSON control characters U+0008, U+0009, U+000A, U+000C or U+000D which SHOULD be serialized as \b, \t, \n, \f and \r respectively. All other Unicode characters SHOULD be serialized "as is", other than U+005C (\) and U+0022 (") which SHOULD be serialized as \\ and \" respectively.