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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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Rename a graph with sparql update

Is possible to rename a graph using sparql update? The only way through that I see is this: INSERT {GRAPH uri:graphNEW {?s ?p ?o}} WHERE {GRAPH uri:graphOLD {?s ?p ?o}}; DROP GRAPH uri:graphOLD but I'm not 100% sure that all the triples and…
ffa
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Sparql query with Blank node can be complex

I read this blog article, Problems of the RDF model: Blank Nodes, and there's mentioned that using blank nodes can complicate the handling of data. Can you give me an example why using blank nodes is difficult to perform a SPARQL query? I do not…
Competo
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What does make a URI derefenceable?

I found a very little information on this matter. What is the difference between dereferenceable and non-dereferenceable URIs? What does it mean to dereference a URI? How does the URI change after it has been derefenced? When reading about linked…
Melron
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get list of desambiguated homonyms from wikipedia / wikidata / linked data

If I search for "George Bush" manually on wikipedia I'll get this page which lists homonyms with short descriptions. I would like to feed my search to an api and get the following info : George H. W. Bush George W. Bush George Bush (biblical…
moodymudskipper
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Importing all definitions from an external JSON Schema

I've been experimenting with JSON Pointers to reference and reuse JSON schemas. Following the examples, I'm able to reference a specific property declared in another JSON schema and everything goes as expected, but I haven't found a way to extend a…
Pascalito
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units of measurement in owl and rdf

I'm creating linked data of materials and their physical properties, and I'm having trouble with setting units for certain properties. My individual material :AlMg3 has some mechanical properties like: :AlMg3 prop:hasTensileStrength "300" . :AlMg3…
Gem
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Problem when trying to reuse external terms using MIREOT Protégé Plugin

I have tried to reference external vocabulary using MIREOT Protégé Plugin. The external ontology is located in this link : http://purl.allotrope.org/voc/afo/REC/2018/07/afo (TTL File : http://purl.allotrope.org/voc/afo/REC/2018/07/afo.ttl). The…
Zakariae Aloulen
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What is the difference between REST and LDP?

first of all I am new to this...REST, RDF, LDP etc. I could able to get an understanding about REST and RDF in a vague manner: REST is a framework where everything is a resource and complex client side requests are converted to URI based structural…
GP92
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Why use owl:Restriction as own:EquivalenceClass's property?

I just start to learn Semantic Web and have a question about restriction class. I dug a while but haven't found any answer yet.. Any help would be much appreciated! From text book, I see examples of define restriction class, they are all about to…
Charles Chow
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Content negotiation using mod_rewrite / RewriteCond rules

I have a use case is to host a set of files (same RDF content with different serialization formats such as RDF/XML, Turtle, and JSON-LD) in Github pages and use a w3id URL as a permanent identifier. Further, I want to have content negotiation on…
Nandana
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In JSON-LD, is it possible to extend a context?

I have a JSON-LD document. { "@id": "VDWW1LL3MZ", "first_name": "Vincent", "last_name": "Willems", "knows":["MartyP"], "@context": { "foaf": "http://xmlns.com/foaf/0.1/", "first_name": "foaf:givenName", "last_name":…
Maarten
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Filtering based on a URI in SParQL

You can run the query below at the Linked MDB SPARQL Explorer. The values of ?imdbID (the last variable) contains IRIs from one of three possible domains (freebase.com, rottentomatoes.com or imdb.com). I would like to know how to apply a filter such…
Ihe Onwuka
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Difference between rdf:seeAlso and rdfs:seeAlso

What is the difference between rdf:seeAlso and rdfs:seeAlso? When I can use rdf:seeAlso and when I can use rdfs:seeAlso? Can you do any examples?
user3582433
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SHACL - Attribute is optional, but if it exists, it has to have once a specific value

a class has an optional attribute. If you use this attribute, you have to set it once to a specific value. All other uses of this attribute are not restricted. The real world example is dcat:themeTaxonomy used in dcat:Catalog in DCAT-AP. If used, it…
Ludger
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Convert huge linked data dumps (RDF/XML, JSON-LD, TTL) to TSV/CSV

Linked data collections are usually given in RDF/XML, JSON-LD, or TTL format. Relatively large data dumps seem fairly difficult to process. What is a good way to convert an RDF/XML file to a TSV of triplets of linked data? I've tried OpenRefine,…
puslet88
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