Linked data refers to using the Web to connect related data that were not previously linked. The data are identified, shared and referenced by Uniform Resource Identifier (URI). The Resource Description Framework (RDF) and the underlying standards like SPARQL are used to encode and link the data

1. Federal Spatial Data Infrastructure
Linked Data Service
Federal Office of Topography swisstopo
Coordination, Geo- Information and Services (COGIS)

2. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
WWW
Agenda
Triple
Store
Linked Data Frontend
swissBOUNDARIES3D
RDF
Serialization
Vocabularies
Linked DataSPARQL HTML
SPARQL
Clients
RDF
Clients
HTML
Clients
Virtuoso Open Source Trifid (open source)
https://ld.geo.admin.chhttps://sparql.geo.admin.ch
• Data
• Vocabularies
• Tools
• Triple Store and
LD Frontend
• Infrastructure

3. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Data
• swissBOUNDARIES3D (2016 and 2017)
• National boundaries
• Cantons
• Districts
• Municipalities
• WGS84 (long/lat) as CRS for geometries to foster the wider
cross-community interoperability and usage

4. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Vocabularies
• Reuse as much as possible existing vocabularies:
• GeoSPARQL
• GeoNames
• schema.org
• Dublin Core
• Wikidata
• DBpedia
• We had to define few properties:
• bfsNumber
• cantonalTerritory
• lakeArea

5. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Vocabularies
5
GeoNames
GeoSPARQL
DBpedia
Dublin Core
schema.org
GeoNames
GeoSPARQL
ld.geo.admin.ch/def/

6. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
RDF Serialization
• GeoTriples
• An R2RML/RML mapping generator/editor
• An R2RML/RML mapping processor
• Extends R2RML and RML to model the transformation of
geospatial data into RDF graphs
• CLI and GUI
• Open Source
• Updates:
• Yearly
• Manual process so far. An update takes circa 1h
• 99% of the process can be automatized

7. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Links
https://ld.geo.admin.ch/boundaries/municipality/351
http://classifications.data.admin.ch/municipality/351
http://www.wikidata.org/entity/Q70
rdfs:seeAlso
https://www.wikidata.org/wiki/Property:P1325
rdfs:seeAlso

8. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Triple Store
• Triple Store and SPARQL Endpoint: Virtuoso OS (7.2)
• GeoSPARQL support is limited
• Only WGS84 as CRS (CRS info to be deleted from the
RDF, otherwise data does not get loaded)
• Built-in spatial functions (no GeoSPARQL functions)
• Spatial queries somehow inaccurate (especially for
point-in-polygon queries)
• Not easily scalable:
• Cannot share the same DB among servers (lock file)
• Replication features not available in the OS version
• No valuable OS (and possibly not java-based) alternative
available for production environments
8

9. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
LD Front End
• Trifid by Zazuko
• Lightweight Linked Data Server and Proxy
• Open Source
• LD Interface to SPARQL
• HTML renderering (with embedded RDF)
• Content-Negotiation
• SPARQL Client based on a “geo-enabled” YASGUI
• Listing of resources in a graph
• Search
9

10. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
10

11. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Infrastructure
• t2.large = 2CPU, 8GiB Mem
• Availability > 98% so far
• Virtuoso has just one backend (it is so far not load-balanced)
11
t2.large
Rancher
Virtuoso
Trifid
upkick
t2.large
Rancher
Trifid
upkick
lb
t2.large
Rancher
Virtuoso
Trifid
upkick
t2.large
Rancher
Trifid
upkick
lb
dev prod

12. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Infrastructure
12
Rancher
Virtuoso
Trifid
upkick
Docker Hub
tenforce/virtuoso/
swisstopo/linkeddata-trifid/
Git Hub
geoadmin/linkeddata-trifid
zazuko/trifid
ld.geo.admin.ch
• After each code commit a new Trifid image is built and
automatically deployed
• Upkick continuously check is a new image is available and in
case launches the deploy

13. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Open issues: ld.geo.admin.ch
• Usage statistics
• Implement «410 Gone» for those resources which are no
more available on the server
• Virtuoso:
• GeoSPARQL support is not optimal
• BBOX used for spatial queries: can lead to inaccurate
results
• Scaling is difficult
• More data will hopefully come

14. www.geo.admin.ch/linkeddataPasquale Di Donato - COGIS
Open issues: Ids
• Most of the data we deal with contains identifiers defined in
the legislation (e.g.)
• Verordnung über das eidgenössische Gebäude- und Wohnungsregister
• EGID, EWID
• Verordnung über die geografischen Namen
• Gemeindeverzeichnis: BFS Number
• Ortschaftenverzeichnis: PLZ
• Verzeichnis der Strassen: ESID
• Verzeichnis der Gebäudeadressen (EGID, EDID, EGAID)
• Verzeichnis der Stationsnamen
• A common vocabulary would help and improve
interoperability among different publication systems. Need to
be:
• Commonly agreed
• «Official»
• Lightweight
• Dynamic