1. Encoding of EPOS Semantics
implementation sample based on final depth (finalDepth) and borehole length (boreholeLength_m)

2. What actually is the Final Depth?
Data, Metadata or Semantic Information?

3. Final Depth is … Final Depth is NOT … a Measurement (data)
a Characterisation (semantic information) of a borehole concerning it's utilisation for various scientific investigations
It can be used for the correlation with seismic profiles
The crystalline in a certain area has been drilled …
a Classification (semantic information) of a borehole regarding it's properties
Final Depth is NOT …
providing information (metadata) about other data

4. Final Depth via RDF/XML (OWL)
<owl:Thing rdf:about="
<rdf:type rdf:resource="
</owl:Thing>
<!-- The statement: KTB has reached a final depth of >
<owl:Thing rdf:about="
<rdf:type rdf:resource="
<drilling:finalDepth>9101</drilling:finalDepth>
<owl:Thing rdf:about="
<drilling:finalDepth>12262</drilling:finalDepth>
<owl:Class rdf:about="
<owl:Class rdf:about="
<rdfs:subClassOf rdf:resource="
</owl:Class>
<owl:Class rdf:about="

5. Retrieving & Filtering via Apache Jena: Filter Class
public static final class FinalDepthPredicate implements Predicate < Statement > {
/** the depth value to be compared with (method "test") */
private final double depth;
/** Constructor with parameter depth */
public FinalDepthPredicate ( double depth ) {
this.depth = depth; }
@Override
public boolean test ( Statement st ) {
Literal finalDepthLiteral = st.getLiteral();
boolean passed = false;
try { //if finalDepth >= depth, passed is set to true
if ( finalDepthLiteral.getDouble() >= depth ) {
passed = true;
} catch (NumberFormatException nfe) {} //nothing to do here, passed already set return passed;

6. Retrieving & Filtering via Apache Jena: Query
Property finalDepthProperty = model.getProperty(" "finalDepth");
// specify a selector based on the property finalDepth
Selector selector = new SimpleSelector ( null, finalDepthProperty, (RDFNode) null);
StmtIterator statements = model.listStatements ( selector );
// instance of a filter for boreholes with a finalDepth >
FinalDepthPredicate predicate = new FinalDepthPredicate ( );
ExtendedIterator<Statement> finalDepthFiltered = statements.filterKeep ( predicate );
finalDepthFiltered.forEachRemaining((Statement st) -> {
System.out.println("Statement: " + st);
});
Retrieving & Filtering via Apache Jena: Result
Statement: [ "12262"]

7. Retrieving & Filtering via Apache Jena: Remarks
Previous solution implements a query where objects are stored as simple literals with no further qualification such as typed literals (e.g. float)
Since the subject of the result (statement, triple) of the query is in turn subject to a database, it can be retrieved via Feature or Catalogue Service

8. Retrieving & Filtering via Apache Jena: (Dis-)Advantage
Well-Known Encoding
Beyond Controlled Vocabularies no further knowledge necessary
Adapter for Catalogue and Feature Service required (the short piece of software shown before)

9. Final Depth via SensorML
<sml:identification>
<sml:IdentifierList>
<sml:identifier>
<sml:Term definition="Identification">
<!-- a Borehole is a Sensor -->
<sml:codeSpace xlink:href="
<sml:value>KTB</sml:value>
</sml:Term>
</sml:identifier>
</sml:IdentifierList>
</sml:identification>
<sml:output name="finalDepth"
xlink:role="
xlink:href="
xlink:title="borehole measurements">
<swe:Quantity>
<swe:uom code="m"/>
<swe:value>9101</swe:value>
</swe:Quantity>
</sml:output>

10. Final Depth via SensorML: Remarks
Combines Data, Metadata and Semantic Information within one encoding
Extension of GML and SWE Common
Access via Feature Service

11. Final Depth via GML Simple Feature Profile
<drilling:Borehole gml:id="KTB"
xmlns:drilling="
xmlns:gml="
xmlns:xlink="
<gml:identifier codeSpace="
<drilling:finalDepth uom="urn:ogc:def:uom:OGC::m">9101</drilling:finalDepth>
<drilling:boreholeLength uom="urn:ogc:def:uom:OGC::m">9151</ drilling:boreholeLength >
</drilling:Borehole>
This can be applied to all elements that can be derived from the GML Measure Type

12. Borehole Length via GSCML Simple Feature Profile
<gsmlp:BoreholeView gml:id="KTB"
xmlns:gml="
xmlns:gsmlp="
xmlns:xlink="
<gml:identifier codeSpace="
<gsmlp:boreholeLength_m>9151</gsmlp:boreholeLength_m>
<gsmlp:finalDepth_m>9101</gsmlp:finalDepth_m>
</gsmlp:BoreholeView>

13. Difference between SensorML & GSCML
GSCML Simple Feature Profile
SensorML
Access via initially unknown syntax elements
A unit of measure is not provided
No semantics provided
Access via well-known syntax elements
A unit of measure is inherently provided
Rich semantical information
Both implementations need terms from a Controlled Vocabulary

14. Final Depth via Observations & Measurements
<om:OM_Observation gml:id="finalDepth"
xmlns:gml="
xmlns:om="
xmlns:swe="
<om:phenomenonTime nilReason="inapplicable"/>
<om:resultTime nilReason="unknown"/>
<om:procedure xlink:href="
<om:observedProperty xlink:href="
<om:featureOfInterest xlink:href="
<om:result>
<swe:Quantity>
<swe:uom code="urn.ogc.def.uom.OGC.m"/>
<swe:value>9101</swe:value>
</swe:Quantity>
</om:result>
</om:OM_Observation>

15. Final Depth via Observations & Measurements: Remarks
Actually the right place for a Measurement
Well-Known Syntax
Strict Separation of Concerns between
Data
Metadata
Semantic Information
However, Data, Metadata and Semantics can be on board of O&M together
Rich semantical information
Feature of Interest
Measuring Method …

16. Final Depth via ISO 19139
Please don't!

17. Final Depth via ISO 19139: Remarks
Actually not the right place for Observations & Measurements
In terms of an Identification, a Classification or a Characterisation of a borehole, ISO metadata do not provide the appropriate means
In terms of data, metadata is the wrong place
Numerical queries (e.g. for final depth) are not possible with standard catalogue service requests

18. Final Depth via CERIF
Really?

19. My personal rank, taking into account data & semantics
SensorML (pragmatic approach, solution for all)
O&M (together with SensorML it describes the world)
RDF/XML & Jena (simply beautiful, at least from the IT-Perspective) …
GML Simple Feature Profile (pragmatic approach, however no Separation of Concerns)
Not recommended, taking into account data & semantics
CERIF
ISO 19139
GSCML Simple Feature Profile (partly contradicts the GML-Approach)

20. General Remarks
Except from GSCML Simple Feature Profile all solutions provide Semantic Information on the basis of Controlled Vocabularies
An access to all solutions can be provided with standardised services with no or little effort regarding extensions
In case of only dealing with semantic information, RDF/XML (OWL) ties for the first place
At least in case of simple features (Final Depth) GML is the most pragmatic approach
In all cases these data have to be stored anywhere
More complex semantic information (modelling, correlation) should be stored with appropriate encoding
After all: finalDepth is a very very (intentionally repeating) simple example

21. But!
Where to maintain and manage such things like Final Depth … and remember: Final Depth is the most basic and simple example in EPOS. Management and Maintenance is not always possible with legacy datasets.
And: Where the h.. do I know from (as a seismologist) that there are Resources that can be queried concerning Final Depth

22. No But! A "Semantic Registry" can be used to "answer all questions" by
Maintaining or Referencing Vocabularies
Managing Repositories of
Service-Endpoints …
Based on Event-Driven Architectures or Reactive Streams (e.g. Akka) a central component does not have to actively harvest data but
Is notified about
Provides registration of
Notifies about
A Borehole could register it's e.g. final depth at the Semantic Registry
WFS
Directly via statement in the Semantic Registry

23. Storing Final Depth
RDB
Triple Store
Data model to be adapted if not based on dedicated O&M model
Deducing not possible without specific adapters
Performance!
After all Final Depth is data and not semantic information
Data model already defined by Controlled Vocabulary
Deducing is the underlying objective
Performance?
Final Depth is in most cases not provided directly

24. Maintenance and Management of Final Depth et al.
Specify appropriate Terms (e.g.
Properties and Resources in RDF/XML
Elements in GML Simple Feature Profiles
CodeList, CodeListValue, CodeSpace, in Metadata, GML, SensorML
Specify Controlled Vocabularies
Investigation Methods
Borehole Properties
Specify Resources and Properties
Final Depth is a Property
The KTB is a Resource
Define Statements
The KTB (Subject) has reached a finalDepth (Predicate) of 9101 (Object)
If possible, specify Ontologies

25. Going further with …
… deduced statements

26. Statements about the Tertiary
The Tertiary (Geological Structure)
has been observed (measured) (Measurement)
by the DFT1 (Borehole, Sensor)
at a depth (Measurand)
of 777.0
The Tertiary (Geological Structure)
has been observed (measured) (Measurement)
by the DFT1 (Borehole, Sensor)
with a gamma-ray (Measurand)
of 0.815
Colloquial Language
The Tertiary has been observed at a Depth of with a Gamma-Ray of during the drilling of the Borehole DFT1

27. The RDF/XML-Statement
<rdf:Description rdf:about="
<drilling:measurement>
<rdf:Description rdf:about="
<drilling:depth rdf:datatype="
</rdf:Description>
</drilling:measurement>
<rdf:Description rdf:about="
<drilling:depth rdf:datatype="
<rdf:Description rdf:about="
<drilling:gamma-ray rdf:datatype="
<drilling:depth rdf:datatype="

28. Remember …
… only standard RDF/XML and a standards-based Controlled Vocabulary is required

29. More Statements
Depth is measured with Borehole-Logging (Investigation Method)
Gamma-Ray is measured with Radioactivity-Logging (Investigation Method)

30. A picture is worth a thousand words

31. A second picture is worth a thousand words as well

32. Storing those kind of statements …
… in a or retrieving from a RDB is not simply possible

33. However
A statement about final depth could be set up with a query to a RDB or a set of service-endpoints, providing information on final depth related borehole requests!