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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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How to compact an @id?

Is it possbile to compact iris in @id via the context? I didn't found a solution for that, without using @base. { "@context": { "MaxMustermann": "http://example.org/MaxMustermann", "name": "https://schema.org/name" …
frm
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Query wikidata for wikipedia urls in multiple langauges

I'm trying to use Wikidata as an intermediary to get from a unique identifier listed in Wikidata (for example VIAF ID) to a Wikipedia description. I've managed to piece together this query to get the Wikipedia page ID from a given VIAF ID…
zkwsk
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How to restrict units in property shapes?

I'm looking to make some SHACL shapes for certain properties in my ontology that have a speicified unit. Example: My instance data would look something like this: otlc:surgeprotector_1 rdf:type otlc:Surgeprotector ; otlc:Nominal_voltage[ …
Robin
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How do I compact and/or frame a json-ld document so that IRI values are expressed succinctly as well as keys?

Given an original JSON-LD document like this example, which defines the sources for some thing1: [ { "@id": "https://example.com/thing1", "https://example.com/sources": [ { "@id": "https://example.com/vocab/countries/EN" …
wu-lee
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Common R2RML mapping file for all the tables

I am working on a project to help the user manually import their data sources in the format of CSV or JSON, then the data will be imported into the data warehouse, after that these data sources will be automate generate to RDF Data cubes with R2RML…
Rio Vo
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solid/react-components: useLDflex() for address

I'm trying to read a user's address from their profile with useLDflex() or useLDflexValue(). When I run this: const address = useLDflex(`[${webId}].vcard_hasAddress`)?.toString() || 'loading...'; console.log('address: ', address); Console…
user3320795
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How to concatenate two variables ogether and output a string in SPARQL

I have three variables ?leaf and ?superclass, and ?supersuperclass containing uri's. Now I would like to end up with a table with 2 columns, one column being the ?leaf label and the other being a concatenation of ?superclass and ?supersuperclass…
Robin
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Is there a possibility to batch a select-query with SPARQL and RDF4J?

I am working with a quite large dataset (around 500Mio-Triples) stored in graphDB Free and running on my local developer machine. I want to do some operations with the dataset with RDF4J and have to SELECT more or less the whole dataset. To do a…
onew4y
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LinkedData links in text

My question is specific about Semantically Linked Data Consider following skos:label "Some Label" A resource can have label which is semantically tagged. I am trying to build data set where label/title contains citations, how can i…
Zafar Ali
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Assuming IRIs when converting legacy JSON documents to RDF knowledge with JSON-LD

I am currently trying to use JSON-LD to make legacy JSON documents machine readable. Now I have a legacy document that contains a list of names. Each of these names references an entity for which I already have further knowledge in my graph and…
aef
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Computing Percentages in SPARQL

I have an ontology (called CODO) about patients of the Covid pandemic. One of our classes is a Cluster and each patient codo:isMemberOf one and only one Cluster. I want to compute the percentage of patients in each Cluster using SPARQL. Also, we…
Michael DeBellis
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RDF, is it valid to have a single rdf:Statement with multiple rdf:predicate triples attached?

As per subject, Is it valid to assert a single rdf:Statement with multiple rdf:predicate triples attached to it? Background: I'm trying to build inferred triples by means of simple rules based on SPARUL (ie, INSERT WHERE…
zakmck
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Owl ontology in protege

I want to create an ontology based on a MeSH RDF descriptor for example pancreas (https://id.nlm.nih.gov/mesh/D010179.html). So far i have created a class using that URI hence its name is D010179. Regarding its properties, how do i form them and how…
Notoriousphd
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Virtuoso: st_intersects() distance between points does not match with precision parameter

The LinkedGeoData site has some examples of SPARQL queries. One example says it retrieves all amenities 100m from Leipzig Central Station. However, the SPARQL query results have much more distance than 100m from the Central Station. The example's…
João Almeida
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SPARQL-query to get data from wikidata not working

I try to get some image links from wikidata by running a SPARQL-query from my local Jena Fuseki instance. I want to merge it with data from my local graph. Unfortunately the query isn't delivering any data but runs and runs instead without any error…
Jan Seipel
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