d3-sparql

This module allows to access data from SPARQL Endpoints in the vein of d3-csv and friends. 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 return the result in a d3 ready data format:

d3.sparql(wikidataUrl, mikeQuery, function(error, data) {
  if (error) throw error;
  console.log(data); // [{'developerName': 'Mike Bostock'}]
})

More examples are provided in the repository.

Features

• Based on d3-require to be in-line with other d3 request code (and assure the same compatibility with browsers.)
• 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.
• A backport to a d3 v3 implementation is provided.

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.
• Only GET requests can be issued in the current version.

Installing

If you use NPM, npm install d3-sparql. Otherwise, download the latest release.

API Reference

The sparql request is based on a d3.request. It implements the sparql function and sets an according request.response which processes the response of the SPARQL endpoint.

# d3. sparql (endpoint, query[, callback]) <>

Returns a new sparql request for the specified SPARQL endpoint with the specified SPARQL query. If no callback is specified, the returned sparql request is not yet issued and can be further configured. If a callback is specified, it is equivalent to calling sparql.get immediately after construction:

d3.sparql(endpoint, query)
    .get(callback);

All other request functions can be used as specified to influence the final request (, except request.response and request.mimeType should not be changed, unless you know what you do, to assure correct working of the sparql request).

Acknowledgement

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