Linked Data - Connect Distributed Data across the Web. What is Linked Data? The recent LinkedData Planet conference in NYC marked, I think, a real transition point.
The conference signaled the beginning movement of the Linked Data approach from the research lab to the enterprise. As a result, there was something of a schizophrenic aspect at many different levels to the conference: business and research perspectives; realists and idealists; straight RDF and linked data RDF; even the discussions in the exhibit area versus some of the talks presented from the podium. Like any new concept, my sense was a struggle around terminology and common language and the need to bridge different perspectives and world views.
Like all human matters, communication and dialog were at the core of the attendees’ attempts to bridge gaps and find common ground. Based on what I saw, much great progress occurred. The reality, of course, is that Linked Data is still very much in its infancy, and its practice within the enterprise is just beginning. Linked Data Defined 1. Yes. 2. No. 3. Linked Data star scheme by example. Linked Data Marketplaces. Why Carry the Cost of Linked Data? – Tom Heath’s Displacement Activities. June 16th, 2010 by Tom Heath In his ongoing series of niggles about Linked Data, Rob McKinnon claims that “mandating RDF [for publication of government data] may be premature and costly“.
The claim is made in reference to Francis Maude’s parliamentary answer to a question from Tom Watson. Personally I see nothing in the statement from Francis Maude that implies the mandating of RDF or Linked Data, only that “Where possible we will use recognised open standards including Linked Data standards”. Note the “where possible”. However, that’s not the point of this post. There’s nothing premature about publishing government data as Linked Data – it’s happening on a large scale in the UK, US and elsewhere. Let’s make a direct comparison between publishing a data set in raw CSV format (probably exported from a database or spreadsheet) and making the extra effort to publish it in RDF according to the Linked Data principles. There are two main reasons: discoverability and reusability. How to publish Linked Data on the Web. This document provides a tutorial on how to publish Linked Data on the Web.
After a general overview of the concept of Linked Data, we describe several practical recipes for publishing information as Linked Data on the Web. This tutorial has been superseeded by the book Linked Data: Evolving the Web into a Global Data Space written by Tom Heath and Christian Bizer. This tutorial was published in 2007 and is still online for historical reasons.
The Linked Data book was published in 2011 and provides a more detailed and up-to-date introduction into Linked Data. The goal of Linked Data is to enable people to share structured data on the Web as easily as they can share documents today. The term Linked Data was coined by Tim Berners-Lee in his Linked Data Web architecture note. Applying both principles leads to the creation of a data commons on the Web, a space where people and organizations can post and consume data about anything. This chapter describes the basic principles of Linked Data. Online Access. Overview The following interfaces exist for online access: Rest Api: provides basic access to a database with a full Open Street Map (OSM) planet file loaded.
Sparql Endpoints: enable queries on databases with a reduced (but hopefully for many applications relevant) subset of the whole data loaded. The Sparql Endpoints come in two flavours: Static: Contains the data extracted from a OSM planet file of a certain date Live: Initially a copy of the static version that is then synchronized with the minutely updates from OSM. As of 2012 February 1st, the Virtuoso database powering the live SPARQL endpoint is not synchronized anymore. A summary of the capabilities of the interfaces are given below.
Features Access to all nodes and ways and their tags of a planet file. Retrieval of data within circular and rectangular area.