SPARQL endpoint available: https://landportal.org/sparqlWhat is RDF?
The Resource Description Framework (RDF) is a standard model for data publishing and interchange on the Web developed by the W3C. RDF is the standard used in a semantic graph database, also referred to as an RDF triplestore.
In the Land Portal, we are storing the information using RDF.
Which triplestore is used to storage the information?
Currently, Virtuoso Open-Source version 7.2 is the triplestore used.
What is SPARQL?
SPARQL, pronounced ‘sparkle’, is the standardized query language for RDF, the same way SQL is the standardized query language for relational databases. The specification of SPARQL query language 1.1 is available and open.
A SPARQL query consists of a set of triples where the subject, predicate and/or object can consist of variables. The idea is to match the triples in the SPARQL query with the existing RDF triples and find solutions to the variables. A SPARQL query is executed on a RDF dataset, which can be a native RDF database (triplestore). These databases have SPARQL endpoints which accept queries and return results via HTTP.
How do I access the data? Is there a SPARQL endpoint available?
Yes, a SPARQL endpoint (https://landportal.org/sparql) is available to query the different graphs.
All our statistical data and Drupal data is accessible as Linked Open Data.
Some examples of SPARQL queries used to retrieve the statistical data in the country pages are available on gitHub.
Graphs
In the Land Portal triplestore, the knowledge is divided by graphs:
| Graph | Contains |
|---|---|
http://data.landportal.info |
Statistical data (Observations) |
http://countries.landportal.info |
Countries (from Regions (Taxonomy)). Countries is a curated subset of Regions taxonomy terms [only the ones with ISO3 code]. |
http://regions.landportal.info |
Contients/subcontinents (from Regions (Taxonomy)). Contients/subcontinents is a curated subset of Regions taxonomy terms [only the ones with UN M.49 alpha code]. |
http://datasets.landportal.info |
Datasets (Taxonomy) (controlled) |
http://indicators.landportal.info |
Indicators (Taxonomy) (controlled) |
http://organizations.landportal.info |
Organizations (CT) (controlled) |
http://library.landportal.info |
Land Library Resources (CT) (Raw from Drupal) |
http://news.landportal.info |
News (CT) (Raw from Drupal) |
http://blog-posts.landportal.info |
Blog Posts (CT) (Raw from Drupal) |
http://events.landportal.info |
Events (CT) (Raw from Drupal) |
http://languages.landportal.info |
Languages (Taxonomy) (Raw from Drupal) |
http://licenses.landportal.info |
Licenses (Taxonomy) (Raw from Drupal) |
http://organization-types.landportal.info |
Organization types (Taxonomy) (Raw from Drupal) |
http://llr-types.landportal.info |
Land Library Resource Types(Taxonomy) (Raw from Drupal) |
| - - - | |
http://regions-drupal.landportal.info |
Regions (Taxonomy) (Raw from Drupal) |
http://datasets-drupal.landportal.info |
Datasets (Taxonomy) (Raw from Drupal) |
http://indicators-drupal.landportal.info |
Indicators (Taxonomy) (Raw from Drupal) |
http://organizations-drupal.landportal.info |
Organizations (CT) (Raw from Drupal) |
http://themes.landportal.info |
Themes (Taxonomy) (Python generated) |
http://landvoc-drupal.landportal.info |
LandVoc Concepts (Taxonomy) (Raw from Drupal) |
http://landvoc.landportal.info |
LandVoc Concepts (Taxonomy) (Curated. Using SKOS) |
Usually, there are more graphs in the triplestore (you can query the triplestore to obtain the whole list)