Overcoming the catch-22 dilemma unlocking the full potential of location-based services as Linked Open Data in real-time ecosystems.

1. OVERCOMING THE
CATCH-22 DILEMMA
UNLOCKING THE FULL POTENTIAL OF
LOCATION-BASED SERVICES AS LINKED
OPEN DATA IN REAL-TIME ECOSYSTEMS.
Raf Buyle, Ziggy Vanlishout
Cristian Vasquez Paulus and Pieter Colpaert
INSPIRE – 2017 - Strasbourg France

2. Flanders Information Agency

3. The cost for re-using public sector
information is too high.

4. Scalable services are expensive
for public administrations

5. The 5-star Flemish Address Registry
lessons learned
The Address Base Registry contains well
over 4 million addresses and their
geographical coordinates.

6. http://data.vlaanderen.be/id/adres/2584882
Persistent Identifiers
URIs1
Dereferenceable HTTP
URIs
Human readable
Links to other
information1
Machine friendly
5-STAR Linked Open Data
The Web as a Blueprint
information in line with
standards (RDF) 1
1 Tim Berners-Lee, https://www.w3.org/DesignIssues/LinkedData.html

7. Linked Data Address Products
A data dump
• all triples in an entire dataset
• http://data.vlaanderen.be/dumps
A subject page
• triples about a specific subject in a dataset
• http://data.vlaanderen.be/id/adres/2584882
A SPARQL endpoint
• triples that correspond to a SPARQL query
• http://data.vlaanderen.be/sparql

8. CPU-cost raises linearly
with amount of queries
Resources on the web, identified by urls through the uniform
interface offered by HTTP can be cached easily
SPARQL endpoints implement a protocol on top of HTTP,
therefore regular HTTP caching can not be applied2
2 Verborgh R. et al. http://linkeddatafragments.org/publications/ldow2014.pdf

9. Verborgh R. et al. http://linkeddatafragments.org

10. Can we balance the CPU-cost
between the client and the server?
A comparison of required processing (filledbars) and datatransfer (dottedlines) shows why ldf scales significantly better.
Verborgh R. et al

11. Addresses LDF
• > 4 Mio addresses are published as Linked Data Fragments
• RDF documents can be compared to ‘tiles’
• Documents contain links to other documents, which allow machines to
browse the dataset
• The document-fragments are visualized on a map,
and cached using the standard HTTP infrastructure

12. TAKE AWAY
@info_vlaanderen @rafke @ziggyvanlishout @pietercolpaert
Scaling Linked Data SPARQL
endpoints is expensive
Overcome catch 22 by
reassessing client server trade-offs.
Linked Data Fragments,
offer a hybrid solution.
New querying paradigm
Demo: https://bit.ly/geo_ldf
API: https://bit.ly/geo_ldf_api

13. Flemish Government
LDF initiatives
Geospatial LDF – Address Registry
• Demo: https://bit.ly/geo_ldf
• API: https://bit.ly/geo_ldf_api
Heritage Thesauri in Flanders - LDF
• Online editor: loveable user interface
• Open API for reading and writing
• Demo: https://thesaurus.onroerenderfgoed.be
• Source: https://github.com/OnroerendErfgoed/atramhasis