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Information Viewpoints and Geoscience Service Architectures

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Matching information meta-models and service interfaces
Presented at AGU, 2007-12-13

Published in: Science
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Information Viewpoints and Geoscience Service Architectures

  1. 1. Information Viewpoints and Geoscience Service Architectures Simon Cox Research Scientist 13 December 2007
  2. 2. Outline • Key viewpoints for earth science information • Feature, field, observation • The value-adding cycle • Mapping the viewpoints to OGC services and chains
  3. 3. Fields vs. objects classic geology: “feature” classic earth-observations: “field” or “coverage”
  4. 4. Conceptual object model: features • Digital object corresponding with identifiable, typed, object in the real world • mountain, road, specimen, event, tract, catchment, wetland, farm, bore, reach, property, license-area, station • Feature-type characterised by specific set of properties • Specimen • ID (name) • description • mass • processing details • sampling location • sampling time • related observation • material • …
  5. 5. Mapped features
  6. 6. Spatial function or field – “coverage” (x1,y1) (x2,y2) • Variation of a property in domain of interest • Property may be multi-component • Domain is often sampled on a grid • Domain extent is scoped by shape/lifetime of feature of interest • Range-type is scoped by type of feature-of-interest
  7. 7. Different cross-sections through same dataset Specimen Au (ppm) Cu-a (%) Cu-b (%) As (ppm) Sb (ppm) ABC-123 1.23 3.45 4.23 0.5 0.34 • A Row summarizes the properties of one feature • A Column = variation of a single property across a domain (i.e. set of locations)
  8. 8. Assignment of property values • For each field in the table the value is either i. asserted • E.g. name, owner, price, boundary (cadastral feature types) i. observed/estimated • E.g. colour, mass, shape (natural feature types) • i.e. error is of interest
  9. 9. Generic pattern for observation metadata An Observation is an action whose result is an estimate of the value of some Property of the Feature-of-interest, obtained using a specified Procedure Feature-of-interest concept reconciles remote and in-situ observations
  10. 10. Three viewpoints: Feature, Coverage, Observation Specimen Au (ppm) Cu-a (%) Cu-b (%) As (ppm) Sb (ppm) ABC-123 1.23 3.45 4.23 0.5 0.34 • A Row gives properties of one feature • A Column = variation of a single property across a domain (i.e. set of locations) • A Cell reflects the result of a single observation
  11. 11. Value-adding chain • Observation/result • estimate of value of a property for a single specimen/station/location • data-capture, with metadata concerning procedure, operator, etc • Coverage • compilation of values of a single property across the domain of interest • data prepared for analysis/pattern detection • Feature • object having geometry & values of several different properties • 1. classified object, snapshot for transport • geological map elements • 2. object created by human activity, artefact of investigation • borehole, mine, specimen
  12. 12. OGC Service stack • Different information-types accessed using different interfaces • Maps – WMS • Features – WFS • Coverages – WCS • Observations – SOS • Each interface is composed of a “set of operations”
  13. 13. SOS getObservation getResult describeSensor getFeatureOfInterest Accessing data using the “Observation” viewpoint WFS/ Obs getFeature, type=Observation WCS getCoverage getCoverage (result) Sensor Register getRecordById WFS getFeature e.g. SOS::getResult == “convenience” interface for WCS
  14. 14. WFS/ SFS The “Sampling Feature Service” viewpoint WFSgetFeature WCS getCoverage getCoverage (property value) SOS getObservation Common data source getFeature (sampling Feature) getFeature (relatedObs/result value) getFeature (relatedObservation) getCoverage (result) Sensor Register getRecordById (procedure) getFeature (featureOfInterest) getObservation (relatedObs) getResult (property value)
  15. 15. WFS The “Domain Feature” viewpoint WCS getCoverage (property value) getFeature SOS getResult (property value) The “Observations are the most primitive” viewpoint #1 – observations are property-value-providers for features ??
  16. 16. WCS Accessing data using the “just the data” viewpoint WFS getFeature/geometry (domain exent) getCoverage SOS getResult (lots of ‘em) (range values) The “Observations are the most primitive” viewpoint #2 – observations are range-value-providers for coverages
  17. 17. Key points • Earth scientists use multiple viewpoints onto their data • These can be reconciled through a robust data model • Service interfaces to the different viewpoints can be composed in various ways, based on a simple set of OGC components
  18. 18. Contact Us Phone: 1300 363 400 or +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au Thank you Exploration & Mining Simon Cox Research Scientist Phone: 08 6436 8639 Email: Simon.Cox@csiro.au Web: www.seegrid.csiro.au
  19. 19. RockSample-A : Specimen DensityItA : Observation Density : Phenomenon Densitometry : ObservationProcedure 2610 kg/T : Measure 2006-11-23 : TM_Instant Leederv ille, WA : Location RockSample-B : Specimen DensityItB : Observation 2580 kg/T : Measure 2005-12-23 : TM_Instant West Leederville, WA :Location +time+result +procedure+observedProperty +featureOfInterest +samplingLocation +density +samplingLocation +time +procedure+observedProperty +featureOfInterest +result +density ProbeItA : Observation Material : Phenomenon Microprobe : Observ ationProcedure MineralDistribution :CV_Coverage 2006-11-24/2006-11-26 : TM_Period RockSample-A : Specimen Leederv ille, WA : Location +observedProperty +procedure +result +time +material +featureOfInterest +samplingLocation RockSample-A : Specimen 2610 kg/T : Measure Leederville, WA : Location +density +samplingLocation RockSample-A : Specimen DensityItA : Observ ation Density : Phenomenon Densitometry : ObservationProcedure 2610 kg/T : Measure 2006-11-23 : TM_Instant Leederville, WA : Location +featureOfInterest +observedProperty +procedure +result +density +time +samplingLocation RockSample-A : Specimen 2610 kg/T : Measure Leederville, WA : Location RockSample-B : Specimen 2580 kg/T : Measure West Leederville, WA :Location +density +samplingLocation +density +samplingLocation ProbeItA : Observation Material : Phenomenon Microprobe : Observ ationProcedure MineralDistribution :CV_Coverage 2006-11-24/2006-11-26 : TM_Period RockSample-A : Specimen DensityItA : Observation Density : Phenomenon Densitometry : ObservationProcedure 2610 kg/T : Measure 2006-11-23 : TM_Instant Leederv ille, WA : Location +procedure+observedProperty +result +time +featureOfInterest +material +featureOfInterest +observedProperty +procedure +result +density +time +samplingLocation MineralDistribution :CV_Cov erage RockSample-A : Specimen 2610 kg/T : Measure Leederville, WA : Location +material +density +samplingLocation Observations, features and coverages Feature summary Property-value evidence Multiple observations one feature, different properties: feature summary evidence A property-value may be a coverage Same property on multiple samples is a another kind of coverage Multiple observations different features, one property: coverage evidence
  20. 20. WFS Operation WFS-Client WFS GetCapabilities() Capabilities() DescribeFeatureType(FeatureType) XML Schema() GetFeature(FeatureType, FilterExpression) Feature Collection () GetGmlObject(ObjectID) Object() Transaction(...) TransactionResponse() Name: Package: Version: Author: WFS-S1 OWS 1.0 Simon Cox
  21. 21. Multiple interfaces to same information? • SOS::GetObservation == WFS::GetFeature(type=Observation) • SOS::GetResult == WCS::GetCoverage • SOS::DescribeSensor == WFS::GetFeature(type=Sensor) or CSW::GetRecordById • “Profile” generic operations • fix one or more parameters
  22. 22. Service profiles • WFS is “soft-typed” • Any feature-type • Query scoped by response model • Strong-typed service = profile of generic service-type • Limit response model • SOS = WFS(feature-type=Observation) • GeoSciML-service = WFS(feature-type=gsml:*) • Spectral Data Service = WCS(domain=wavelength) • Limit query model • Queriable properties = subset of response model • Conformance-levels? • Level 0 – spatial queries only • Level 1 – only these props • Level 2 – complete WFS

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