the rdf report card: beyond the triple count
TRANSCRIPT
Leigh Dodds@ldodds
http://kasabi.comhttp://slideshare.net/ldodds
The RDF Report Card
Beyond the Triple Count
26th September 2011
SemTechBiz 2011
Triple counts tell us nothing
Triple counts are not a quality indicator
http://dbpedia.org/resource/London
6 triples for Population Density
Property Count Value
http://dbpedia.org/ontology/PopulatedPlace/populationDensity 2 4807.04806.971873853451
http://dbpedia.org/ontology/populationDensity 2 4806.9718744807.000000
http://dbpedia.org/property/populationDensityKm 1 4807
http://dbpedia.org/property/populationDensitySqMi 1 12450
12 triples for Location (1)
Property Count Value
georss:point 1 51.507222222222225 -0.1275
geo:geometry 1 POINT(-0.1275 51.5072)
geo:lat 1 51.507221
geo:long 1 -0.127500
12 triples for Location (2)Property Count Value
dbpprop:latd 1 51
dbpprop:latm 1 30
dbpprop:lats 1 26
dbpprop:latns 1 N
dbpprop:longd 1 0
dbpprop:longm 1 7
dbpprop:longs 1 39
dbpprop:longew 1 W
~4.6m redundant triples
Triple counts don't indicate utility
http://bbc.co.uk/programmes
2.5 million unique users per week, 60 req/s*
*http://www.guardian.co.uk/media/pda/2011/apr/06/bbc-yves-raimond
http://bbc.co.uk/programmes
Dataset is less than 50 million triples
Beyond the Triple Count
Dataset Information Spectrum
High DetailLow Detail
Summary and overview of dataset content
Detailed data model documentation & guides
Dataset Information Spectrum
High DetailLow Detail
Summary and overview of dataset content
Detailed data model documentation & guides
More Information
Dataset Information Spectrum
High DetailLow Detail
● Title, Description● Provenance● Publication dates● Licensing● Usage cues● Related datasets
Metadata
Dataset Information Spectrum
High DetailLow Detail
Scope ● What types of entity?● How many of each type?● Coverage
● Geographic● Events (time)
Dataset Information Spectrum
High DetailLow Detail
Structure ● URI Scheme● Vocabulary meshing
● How is a person described?
Dataset Information Spectrum
High DetailLow Detail
Internals ● List of Schemas & RDF terms● Class/property usage counts● Triple counts● Named graph structure● Source files
RDF Report Card Example
Summarising Content of a Dataset
● Find all classes in all datasets in Kasabi
● Tag each class against a pre-defined set of categories● Customized version of top-level schema.org
classes
● Generate a report card for each dataset listing types of entity
Report Card Categories
Ordnance Survey
http://beta.kasabi.com/dataset/ordnance-survey-linked-data
BBC Music
http://beta.kasabi.com/dataset/bbc-music
British National Bibliography
http://beta.kasabi.com/dataset/british-national-bibliography-bnb
NHS Performance Data
http://beta.kasabi.com/dataset/nhs-performance-data
Summary
● Triple counts tell us nothing● Vital to present the quality & utility of our data
● Data publishing platforms should support this
● "Progressive disclosure"● Right detail at the right time
● Dataset analysis can generate useful summaries● e.g. an RDF report card
