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Questions tagged [linked-data]

Linked Data refers to a set of best practices for publishing data on the Web under the Semantic Web standards (RDF, SPARQL, etc.). Please consider asking your question on https://opendata.stackexchange.com, if your question is not closely related to programming or is related to a particular Linked Data dataset.

T. Berners-Lee outlines four principles of linked data in his "Linked Data" note:

  1. Use URIs as names for things
  2. Use HTTP URIs so that people can look up those names
  3. When someone looks up a URI, provide useful information, using the standards (RDF*, SPARQL)
  4. Include links to other URIs, so that they can discover more things
371 questions
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What do the parameters of DBpedia Spotlight mean?

I am interested in using DBpedia Spotlight. However, we need to insert a value to the two parameters confidence and support. What do these two parameters really mean? I want to identify the significant, prominent n-grams in the text. In that case,…
J Cena
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RDFlib: Add triples to graph in bulk

I am parsing triple files and adding the triples into my local triplestore. Code Snippet: graph = ConjunctiveGraph('Sleepycat') graph.open("mytriplestore", create=False) g = Graph() g.parse("filename.ttl", format="ttl") for t in g: …
RDangol
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What is the difference between a relation and a property in a Linked Data ontology?

The wikipedia article ontology components describes relations as one of the components of an ontology. It states that relations "specify how objects are related to other objects". Is-a/sub-class and partOf relations are provided as examples. I am…
Natkeeran
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Simple versioning in RDF data

Many datasets have a history of changes. Making historical data available as Linked Data can be a challenge. The general case I am considering is one where a dataset has data about things that have properties that can change in time. An example…
F.J. Knibbe
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Why multiple URLs for a single wikidata concept?

Each item or property of wikidata has a persistent URI that you can obtain by appending its ID. For example, the property P1566 (representing GeoNames ID) has the following URI http://www.wikidata.org/prop/direct/P1566 You can also access to this…
Jane Foster
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Bulk edit subject of triples in rdflib

I create an rdflib graph by parsing records from a database using rdflib-jsonld. However, the subject of triples has a missing / from the url. To add it, I use the following code: for s,p,o in graph1: print 'parsing to graph2. next step…
kurious
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How can I tell if a resource/entity is a class or instance

In RDF/RDFS/OWL, how can I tell if an entity is an purely an instance or also a class? I understand that class entities are also instances, since they are instances of the "class" entity and subclasses of other classes. However, I believe some…
LazerSharks
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Use a numeric value as string value in SPARQL

Is possible to use somehow a numeric value as a string value in a SPARQL query? For instance, consider the following RDF data, query, and desired result: Knowledge base @prefix gr: . @prefix xsd:…
ffa
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How to get intersection-like behavior with SPARQL 1.1's VALUES?

Using SPARQL 1.1's values, the following query returns all predicates with Einstein or Knuth as the subject (along with their labels). PREFIX dbp: SELECT DISTINCT ?sub ?outpred ?label { VALUES ?sub {…
kdbanman
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What is the proper value representation of a schema.org/polygon when used in JSON-LD?

The data representation I will try to use for a RESTful API is JSON-LD and the vocabulary I intend to use are those from schema.org. In the vocabulary schema.org/GeoShape, it says that polygons are expected to be on text format but it doesn't…
Abel Callejo
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Retrieving dbpedia-owl:type value of resource with dbpedia-owl:wikiPageRedirect value?

Visitng http://dbpedia.org/resource/Cupertino shows the DBpedia RDF information about Cupertino. As you can see, it has, among others, the property and value: dbpedia-owl:type dbpedia:City However, this query on the DBpedia endpoint returns no…
SuperUser01
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Can't retrieve movies with high IDs from LinkedMDB with SPARQL

I'm running the following query at the LinkedMDB SPARQL endpoint and it works. With it, I get all the information that I need about the director of the movie with id 72, which is Titanic, so I get information about James Cameron. PREFIX mdb:…
chomp
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Do URIs used in RDF need to be dereferenceable in Jena?

I'm looking over the Jena tutorial, An Introduction to RDF and the Jena RDF API, and am specifically looking at Tutorial01.java. The PersonURI is very vague, as it is defined as: static String personURI = "http://somewhere/JohnSmith"; Does this…
WildBill
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how to filter out non-resource values in DBpedia SPARQL query?

I have this query to return eras for philosophers that works: PREFIX dbpedia-owl: PREFIX dbpprop: SELECT ?philosopher ?era WHERE { ?philosopher a dbpedia-owl:Philosopher ; …
Michael West
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How to set up URIs for a classification that has new editions

I have a classification that at regular times has a new edition. Concepts are added, the structure may change, or properties like classification codes may change, but most concepts stay and should have stable uri's. I want to know what is the best…
harryd
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