zazuko / d3-sparql

Query a SPARQL endpoint with a SELECT query and get the data ready to be used with d3js

d3-sparql

This module lets you request data from SPARQL endpoints in the vein of d3-csv and friends. It is generating a JSON structure from SPARQL query results, you can use that in any way you like in your code, with or without D3.

The access through a SPARQL endpoint allows a faster and more efficient data preparation (once you got the hang of SPARQL and the RDF data model). Ultimately it keeps visualizations up to date. Think of SPARQL endpoints as the most flexible API imaginable.

Define the SPARQL query and endpoint:

// Author of Q3011087 (D3.js)
var mikeQuery = `SELECT ?developerName WHERE {
  wd:Q3011087 wdt:P178 ?developer.
  ?developer rdfs:label ?developerName.
  FILTER(LANG(?developerName) = 'en')
}`

wikidataUrl = 'https://query.wikidata.org/bigdata/namespace/wdq/sparql'

To query the endpoint and get the result:

d3.sparql(wikidataUrl, mikeQuery).then((data) => {
  console.log(data); // [{'developerName': 'Mike Bostock'}]
})

More examples are provided in the repository.

Features

• Transformation of XSD Datatypes (e.g. xsd:dateTime, xsd:boolean, ...) to native JavaScript types.
• Reformatting of the JSON Structure to a d3 style layout while using the provided variables names of the SPARQL Query.

Limitations

• Only SELECT queries are supported. (This provides a projection of the graph data onto a table structure used by d3.)
• Currently only supports endpoints which are able to respond with application/sparql-results+json.

Installing

Using NPM: npm install d3-sparql. You can also use a CDN, for instance https://www.jsdelivr.com.

See CHANGELOG for details about available versions.

API Reference

This package adds a sparql function to the global d3 object: d3.sparql(endpoint, query, options = {}).

# d3. sparql (endpoint, query[, options = {}]) <>

options is an optional object that will get merged with the second argument of fetch().

d3.sparql(endpoint, query)
  .then((data) => …);

Acknowledgement

The initial development of this library by Zazuko was supported by the City of Zürich.