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Service Platforms

Service Platforms make heritage data available for a specific purpose. To do so, they need to find, access, understand and transform datasets.

Find datasets​

To get a quick overview of datasets available, you can use the Dataset Register website. For automation, developers will want to use the Dataset Register SPARQL endpoint.

Access datasets​

For each relevant dataset, look up its distributions. There are two types of RDF distribution:

  • data dumps are files that Service Platforms can download to read and process in their own infrastructure;
  • SPARQL endpoints allow you to directly query the data.

For example, the dataset Gouda Timemachine Linked Open Data has both a data dump (at https://www.goudatijdmachine.nl/omeka/files/goudatijdmachine.nt.gz) and a SPARQL endpoint (at https://www.goudatijdmachine.nl/sparql/repositories/gtm).

Using SPARQL​

To use the SPARQL endpoint, start with a simple SELECT query using the cURL command-line tool:

curl -X POST https://www.goudatijdmachine.nl/sparql/repositories/gtm --data 'query=SELECT * WHERE { ?s ?p ?o} LIMIT 10'
s,p,o
http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#Property
http://www.w3.org/1999/02/22-rdf-syntax-ns#Property,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/2000/01/rdf-schema#Class
http://www.w3.org/2000/01/rdf-schema#Class,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/2000/01/rdf-schema#Class
http://www.w3.org/2000/01/rdf-schema#subPropertyOf,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#Property
http://www.w3.org/2000/01/rdf-schema#subPropertyOf,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/2002/07/owl#TransitiveProperty
http://www.w3.org/2000/01/rdf-schema#subClassOf,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#Property
http://www.w3.org/2000/01/rdf-schema#subClassOf,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/2002/07/owl#TransitiveProperty
http://www.w3.org/2000/01/rdf-schema#domain,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#Property
http://www.w3.org/2000/01/rdf-schema#range,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#Property
http://www.w3.org/2002/07/owl#sameAs,http://www.w3.org/1999/02/22-rdf-syntax-ns#type,http://www.w3.org/1999/02/22-rdf-syntax-ns#Property

You may also want to use any of the available SPARQL clients, such as Comunica:

npm install -g @comunica/query-sparql
comunica-sparql sparql@https://www.goudatijdmachine.nl/sparql/repositories/gtm \
  "SELECT * WHERE { ?s ?p ?o} LIMIT 10"

For more information about querying with SPARQL, see the SPARQL specification.

Understand datasets​

Transform data​

Service Platforms may need to transform source data to make it usable in the Platform and its UIs.