The document provides guidelines for publishing data as Linked Data. It discusses identifying appropriate data sources, reusing existing vocabularies and non-ontological resources, generating RDF data from relational databases or geometrical data using tools like R2O, ODEMapster and geometry2rdf, and publishing the data on the web by resolving URIs. The Ontology Engineering Group at Universidad Politécnica de Madrid has published Spanish geospatial and statistical data as part of projects like GeoLinkedData following these guidelines.

1. Methodological Guidelines for
Publishing Linked Data
Boris Villazón-Terrazas, Asunción Gómez-Pérez, and Óscar Corcho
Facultad de Informática, Universidad Politécnica de Madrid
Campus de Montegancedo sn, 28660 Boadilla del Monte, Madrid
http://www oeg upm nethttp://www.oeg-upm.net
{bvillazon,asun,ocorcho}@fi.upm.es
Phone: 34.91.3366605, Fax: 34.91.3524819
Cochabamba, Bolivia
May, 2011

2. ToC
• Ontology Engineering Group
• Introduction to Linked Data
• Guidelines for Publishing Linked Data
• Demo
2

3. ToC
• Ontology Engineering Group
• Introduction to Linked Data
• Guidelines for Publishing Linked Data
• Demo
3

4. People
• Director: A. Gómez-Pérez
• Research Group (38 people)
• 2 Full Professors
• 6 Associate Professors
• 1 Assistant Professor
• 6 Postdocs
• 14 PhD Students
• 6 MSc Students
• 4 Software Engineers
• Management (5)
• 3 Project Managers• 3 Project Managers
• 1 System Administrator
• 1 Secretary
• 80+ Past Collaborators• 80+ Past Collaborators
• 15+ visitors
4
http://www.oeg-upm.net

5. Students from...
France
G
Lithuania
Italy
France
Serbia
Macedonia
Germany
MalaysiaColombia
India
Ecuador
Cameroon
Bolivia
Ecuador
5

6. > 30 Research projects
1999 20022000 2001 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 20131999 20022000 2001 2003 2004 2005 2006 2007
Katalyx
Group
IGN/RAE/AMPER/XMEDIA
2008 2009 2010
E ñ Vi t l/ IO!/B diPLATA
WHO/IGN/BNE/FAO
2011 2012 2013
ContentWeb
20 Ac Especiales/Complementarias
Servicios Semánticos
REIMDOC (FIT) Red/Gis4Gov/11811/UPnP/UpGrid/Autores3.0/WEBn+1
GeoBuddies
España Virtual/mIO!/BuscamediaPLATA
BabelData / myBigData
HA98-0002
MKBEEM
O t W b
HF02-0013
20 Ac. Especiales/Complementarias
SEEMP
NeOnOntoWeb
Esperonto
PIKON
Knowledge Web
NeO
ADMIRE
DynaLearn
OntoGrid
Marie Curie
SemSorGrid4Env
SEALS
MONNET
Company EU Project Coordinators
SCALUS
PlanetData
Wf4Ever
6
Company EU Project Coordinators
Spanish Projects EU Project Participation

7. Collaboration with international companies
7

8. Collaboration with other research groups
Univ. of Amsterdam
i f d
DFKI
Univ. of Augsburg
Univ. of Karlsruhe
U i f K bl
KSL. Stanford Univ.
Univ. of Wien
Univ. of NR & ALS
Univ. of Innsbruck
Free Univ. of Amsterdam Univ. of Koblenz
Univ. of Hannover
Univ. of Mannheim
Univ of Bielefeld
Univ. of Brasilia
Univ. of Bielefeld
Forschungszentrum Informatik
Univ. of Galway (DERI)
Free Univ. of Brussels
Úniv. of Zurich
Open University
O f d U i it
Ústav Informatiky
Oxford University
Univ. of Manchester
Univ. of Liverpool
Univ of Sheffield
Academy of Sciences
Univ. of Sheffield
Univ. of Aberdeen
Univ. of Edinburgh
Univ. of Southampton
CNR
Univ of Trento
Univ. of Tel Aviv
8
Univ. of Southampton
Univ. of Hull
Univ. of Trento
Univ. of Bolzano
INRIA
Univ. of Athens
TUC

9. Research Areas
2004 2008
Internet
of Things
Semantic e-Science
(Data Integration,
Semantic Grid)
Ontological Engineering
1995Semantic Grid) 1995
(S i l) N l(Social)
Semantic
Web
Natural
Language
Processingg
19972000
9

10. Linked Data in OEG
• GeoLinkedData is an open initiative whose aim is to
enrich the Web of Data with Spanish geospatial data.p g p
http://geo.linkeddata.es
• El Viajero Linked Data is project that focuses on the
integration of the contents produced by newspapers
and digital platforms belonging to Prisa Groupand digital platforms belonging to Prisa Group.
http://webenemasuno.linkeddata.es/
• A project with the Biblioteca Nacional to publish the
library information as Linked Data.y
http://cultura.linkeddata.es/visualizer/
10

11. Linked Data in OEG
• Tools for generating and cosuming Linked Data, e.g.,
• geometry2rdf http://www oeg upm net/index php/downloads/151 geometry2rdf• geometry2rdf http://www.oeg-upm.net/index.php/downloads/151-geometry2rdf
• map4rdf http://oegdev.dia.fi.upm.es/projects/map4rdf/
• Spanish Thematic Network of Linked Data
http://red.linkeddata.esp
» Group leader: Ontology Engineering Group
» 19 Research Groups
» 4 companies» 4 companies
11

12. ToC
• Ontology Engineering Group
• Introduction to Linked Data
• Guidelines for Publishing Linked Data
• Demo
12

13. Classic Web
MovieDB
Data exposed to
the Web viathe Web via
HTML, pdf, etc.
CIA
World
FactBook
13
© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig

14. Classic Web
Information from
single pagesComplex queries
l i l
s g e pages
can be found via
search engines
over multiple
pages / data
?
sea c e g es
sources?
14
© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig

15. What do we actually want?
• Use the Web like a single global database
MovieDB
CIA
World
FactBook
15
© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig

16. Linked Data enables such Web of Data
Global Identifier: URI (Uniform Resource Identifier) which is a string of characters usedGlobal Identifier: URI (Uniform Resource Identifier), which is a string of characters used
to identify a name or a resource on the Internet.
Data Model: RDF (Resource Description Framework), which is a standard model
for data interchange on the Web
Access Mechanism: HTTP
Connection: Typed Links
8000000
“Even the Rain”
http://cia.../Bolivia
http://imdb.../TLLuvia
http://.../population
http://.../name
http://.../filming_location
p
MovieDB
CIA
World
FactBook
16
© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig

17. In a nutshell
• An extension of the current• An extension of the current
Web…
• … where information and servicesdata
are given well-defined and explicitly
represented meaning, …
• … so that it can be shared and used
by humans and machinesby humans and machines, ...
• ... better enabling them to work in
cooperation
• How?
• Promoting information exchange by
tagging web content with machine
processable descriptions of its
meaning.
A d t h l i d i f t t• And technologies and infrastructure
to do this
• And clear principles on how to
publish data
17
publish data

18. The four principles (Tim Berners Lee, 2006)
1. Use URIs as names
for things
• http://www.w3.org/D
esignIssues/Linkedfor things
2. Use HTTP URIs so
that people can look
esignIssues/Linked
Data.html
that people can look
up those names.
3. When someone looks
http://www.ted.com/talks/tim_berners_lee_on_the_next_web.htmlhttp://www.ted.com/talks/tim_berners_lee_on_the_next_web.html
up a URI, provide
useful information,
i th t d dusing the standards
(RDF*, SPARQL)
4 Include links to other4. Include links to other
URIs, so that they can
discover more things.discover more things.
18

19. RDF – Resource Description Framework
W3C d ti• W3C recommendation
RDF is a basic KR language based on semantic networks• RDF is a basic KR language based on semantic networks
• Useful to represent metadata and describe any type of• Useful to represent metadata and describe any type of
information in a machine-accesible way (aka data
model)
• Resources are described in terms of properties and
property values using RDF statement
St t t t d t i l i ti f• Statements are represented as triples, consisting of a
subject, predicate, and object [S,P,O]
Subject Object
property
19
Statement
© Slide adapted from “RDF and RDF Schema”- Raúl García et al.

20. RDF - Example
“Alex Villazón”Alex Villazón
hasName
hasColleague
http://upb.edu/Alex http://upb.edu/Hugo
htt // b d /B t
hasColleague
“M l ”http://upb.edu/Beto “Male”
• For practical purposes, specially if handwritten, URIs are shortened using XML namespaces
• xmlns:upb=“http://upb edu/”
hasSex
xmlns:upb http://upb.edu/
• upb:Alex is equivalent to http://upb.edu/Alex
• RDF serializations: XML, N3, N-Triple
“Alex Villazón”
person:hasName
upb:Alex upb:Hugo
person:hasColleague
person:hasColleague
20
upb:Beto “Male”
person:hasSex
© Slide adapted from “RDF and RDF Schema”- Raúl García et al.

21. RDF - SPARQL
“Alex Villazón”
person:hasName
person hasColleag e
upb:Alex upb:Hugo
person:hasColleague
person:hasColleague
• Query: “Tell me who are the persons who have Hugo as colleague”
upb:Beto “Male”
person:hasSex
upb:Hugo?
person:hasColleague
• Result: upb:Alex and upb:Beto
SPARQL l f RDF W3C d i• SPARQL query language for RDF. W3C recommendation
SELECT ?s
WHERE { ?s person:hasColleague upb:Hugo.}
21© Slide adapted from “RDF and RDF Schema”- Raúl García et al.

22. So does that mean I have to publish my data as Linked Data, now?
• But, why?
• What was your incentive to publish an HTML page in 1990?
• Share data in documents and because your neighbor
was doing itwas doing it
• So, why should we publish Linked Data in 2011?, y p
• Share data as data and because your neighbor is doing it
22
© Slide adapted from “Introduction to Linked Data”- Juan Sequeda

23. And guess who is starting to publish Linked Data now?
• UK Government• UK Government
• US Government
• BBC
• Open Calais
• Freebase
• NY Times
• CNET
• Dbpedia• Dbpedia
• ….
23

24. Linked Open Data evolution
 2007
 2008
 2009
2424

25. Linked Open Data
2010
25
http://richard.cyganiak.de/2007/10/lod/

26. ToC
• Ontology Engineering Group
• Introduction to Linked Data
• Guidelines for Publishing Linked Data
• Demo
26

27. Guidelines for Publishing Linked Data
27

28. Guidelines for Publishing Linked Data
28

29. Identification of the data sources
• Guidelines based on the Open Data Manual 1
• Two possibilities
• To find the data sources already available in a public data
catalog, e.g., Aporta project 2
• To get an agreement with a particular government body to
publish its data sources, e.g., GeoLinkedData - IGNp g
29
1 http://opendatamanual.org/
2 http://aporta.es

30. GeoLinkedData
Identification of the data sources
IGN
National Geographic Institute of Spain
Agreement with the IGN
g p p
Oracle & MySQL
Data sources available
in a public data catalog
INE
National Statistic Institute of Spain
in a public data catalog
30

31. IGN & INE
Identification of the data sources
Year
Industry Production IndexProvince
31

32. Guidelines for Publishing Linked Data
32

33. Ontology
Vocabulary Modelling
• An ontology is an engineering artifact, which provides:
• A set of terms
• A set of explicit assumptions regarding the intended meaning of the terms.
• Almost always including concepts and their classification
• Almost always including properties between concepts
Shared nderstanding of a domain of interest• Shared understanding of a domain of interest
• Ontologies expressed in OWL or RDF(S), both based on RDFOntologies expressed in OWL or RDF(S), both based on RDF
33

34. Reuse available vocabularies
Vocabulary Modelling
Search for suitable
vocabularies
Linked Open Vocabularies
are there
suitable
vocabularies?
Build the vocabulary by
reusing available
vocabularies
Yes
No
34
…

35. Reuse available non-ontological resources
Vocabulary Modelling
Highly reliable Web Sites
Search for suitable
non-ontological resources
Domain-related sites
Government CatalogsGovernment Catalogs
are there
suitable
resources?
Build the vocabulary by
transforming available
resources
Yes
No
Build the vocabulary from
scratch
35

36. GeoLinkedData
Vocabulary Modelling
scv:Dimension
scv:Item
scv:Dataset
WGS84 Geo
Positioning: an RDF
vocabulary
hydrographical
phenomena (riversphenomena (rivers,
lakes, etc.)
Vocabulary for
instants, intervals,, ,
durations, etc.
Ontology for OGC
Geography Markup
Language
Names and
international code
systems for
territories and
groupsg g
Classes 33 33
Object Properties 44 44
http://neon-toolkit.org/
j p
Data Properties 318 318
36

37. Guidelines for Publishing Linked Data
37

38. Generation of the RDF Data
INEINE
NOR2O
ODEMapster
IGNIGN
IGNIGN
GeospatialGeospatial
columncolumn
Geometry2RDF
38

39. NOR2O
Industry Production Index Year
Generation of the RDF Data
Industry Production Index
ProvinceProvince
NOR2O
39

40. R2O & ODEMapster
R O is an extensible fully declarative language to describe
Generation of the RDF Data
• R2O is an extensible, fully declarative language to describe
mappings between relational database schemas and ontologies.
• The ODEMapster processor generates RDF instances from
relational instances based on the mapping description
expressed in the R2O document
40
www.oeg-upm.net/index.php/en/downloads/9-r2o-odempaster

41. R2O & ODEMapster
Generation of the RDF Data
• Creation of the R2O Mappings
41

42. R2O & ODEMapster
Generation of the RDF Data
Excerpt of the R2O documentExcerpt of the R2O document
42

43. geometry2rdf
Generation of the RDF Data
• Tool for generating RDF from geometrical information
• The geometry could be available in GML or WKT
• The RDF generated follows our Geometry Model
43
http://www.oeg-upm.net/index.php/en/downloads/151-geometry2rdf

44. geometry2rdf
Generation of the RDF Data
Oracle STO UTIL packageOracle STO UTIL package
SELECT TO_CHAR(SDO_UTIL.TO_GML311GEOMETRY(geometry))
AS Gml311Geometry
FROM "BCN200"."BCN200_0301L_RIO" c
WHERE c.Etiqueta='Arroyo'
44

45. geometry2rdf
Generation of the RDF Data

46. Geometry Model
Generation of the RDF Data
geoes: http://geo.linkeddata.es/
geo: http://www.w3.org/2003/01/geo/wgs84_pos#
geoes:ontology/Geometría
rdfs:subClassOf rdfs:subClassOf
geoes:ontology/Polígonogeoes:ontology/Curvageo:Point
rdfs:subClassOf
rdfs:subClassOf
rdfs:subClassOf
3939geo:lat geo:long
Collection of 2 or
Collection of 3 or
formadoPor formadoPor
more geo:Points
Collection of 3 or
more geo:Points
46

47. RDF generated according to our Geometry Model
Generation of the RDF Data
1 2
0
0
47

48. URI Generation
Generation of the RDF Data
• URIs are extremely relevant in this process since
they are the key for the alignment of heterogeneousthey are the key for the alignment of heterogeneous
resources that come from different data sources.
• Cool URIs 1
• UK Cabinet Office 2
• Examples:
http://geo.linkeddata.es/ontology/{class/property}
http://geo.linkeddata.es/ontology/Lago
http://geo linkeddata es/resource/dataset/type/{resourcename}http://geo.linkeddata.es/resource/dataset/type/{resourcename}
http://geo.linkeddata.es/resource/Provincia/Madrid
48
1 http://www.w3.org/TR/cooluris/
2 http://www.cabinetoffice.gov.uk/media/301253/puiblic sector uri.pdf

49. Provenance Information
Generation of the RDF Data
• It is relevant
• to manage the provenance information of the resources• to manage the provenance information of the resources
• to establish the license of the information
• Example
49
Pubby: http://www4.wiwiss.fu-berlin.de/pubby/

50. Guidelines for Publishing Linked Data
50

51. Publication of the RDF data
map4rdf
map4rdfhttp://oegdev.dia.fi.upm.es/projects/map4rdf/
SPARQLLinked DataHTML
PubbyIncluding Provenance Pubby
Pubby 0.3
Including Provenance
Support
http://www4.wiwiss.fu-berlin.de/pubby/
51
Virtuoso 6.1.0

52. Guidelines for Publishing Linked Data
52

53. Data Cleansing
• To find possible errors, identified by Hogan et al.
• http-level issues such as accessibility and derefencability• http-level issues, such as accessibility and derefencability,
e.g., HTTP URIs return 40x/50x errors
• reasoning issues such as namespace without vocabulary,
e.g., rss:item term invented
• malformed/incompatible datatypes, e.g., “true” as xsd:int
• To fix the identified errors
• Example, encoding URIs
• Special characters á é ñSpecial characters á, é, ñ
• http://geo.linkeddata.es/resource/Provincia/M%C3%A1laga
53

54. Guidelines for Publishing Linked Data
54

55. Linking the RDF Data
Identify suitable data sets
li ki t t
http://ckan.net
as linking targets
Discover relationships
between data items
Silk FrameworkLIMES
http://aksw.org/Projects/limes http://www4.wiwiss.fu-berlin.de/bizer/silk/
Validate the relationships
discovered sameAs Validator
http://oegdev.dia.fi.upm.es:8080/sameAs/
55

56. GeoLinkedData
Linking the RDF Data
GeoLinked
Data
GeoNamesDBPedia
…. …. ….
http://sws.geoname
s.org/6355233/
http://geo.linkeddata
.es/.../Madrid
http://dbpedia.org/re
source/Madrid
56
…. …. ….

57. sameAs Validator
Linking the RDF Data
http://oegdev.dia.fi.upm.es:8080/sameAs/
57

58. Guidelines for Publishing Linked Data
58

59. Register the dataset into CKAN Registry
Enable Effective Discovery
• Add the dataset to CKAN, the open registry of data
and content packagesand content packages
• Minimum information• Minimum information
• Name, unique ID for your data set on CKAN
• Title, full name of your data set, y
• URL, link to the data set home page
59
http://www.w3.org/wiki/TaskForces/CommunityProjects/LinkingOpenData/DataSets/CKANmetainformation

60. Sitemap protocol
Enable Effective Discovery
• Used by web crawlers
• Efficiently find all your content & discover
what has been updated
http://sitemaps.org/
A i fil i i f i di URLA sitemap file contains information regarding one or more URLs on
your Web site. The information that is stored there helps search
engines better spider your website.
60

61. Sindice: the best RDF search engine
Enable Effective Discovery
61

62. sitemap4rdf
Enable Effective Discovery
• Simple command line tool
• Sends a SPARQL query to list all URIs
• Generates sitemap• Generates sitemap
it 4 df htt // it / l htt // it / /sitemap4rdf http://yoursite/sparql http://yoursite/resource/
Example:
it 4 df if i th SPARQL d i t
sitemap4rdf http://geo.linkeddata.es/sparql http://geo.linkeddata.es/
• run sitemap4rdf specifying the SPARQL endpoint
and the prefix of the URLs to include in the Sitemap
62
http://lab.linkeddata.deri.ie/2010/sitemap4rdf/

63. Submit the sitemap location - Sindice
Enable Effective Discovery
• http://sindice.com/main/submit
63

64. Submit the sitemap location - Google
Enable Effective Discovery
• https://www.google.com/webmasters/tools/
64

65. ToC
• Ontology Engineering Group
• Introduction to Linked Data
• Guidelines for Publishing Linked Data
• Demo
65

66. DEMODEMO
http://geo linkeddata es/browserhttp://geo.linkeddata.es/browser
66

67. Provinces
67

68. Capital of Province
68

69. Provinces – Industry Production Index
69

70. Beaches
70

71. DEMODEMO
http://webenemasuno linkeddata es/http://webenemasuno.linkeddata.es/
71

72. Trips
72

73. Guide Locations
73

74. Guide
74

75. Future Work
75
Streaming resources

77. Methodological Guidelines for
Publishing Linked Data
Boris Villazón-Terrazas, Asunción Gómez-Pérez, and Óscar Corcho
Facultad de Informática, Universidad Politécnica de Madrid
Campus de Montegancedo sn, 28660 Boadilla del Monte, Madrid
http://www oeg upm nethttp://www.oeg-upm.net
{bvillazon,asun,ocorcho}@fi.upm.es
Phone: 34.91.3366605, Fax: 34.91.3524819
Cochabamba, Bolivia
May, 2011