Implementing distributed geoscience information systems using Open GIS Web Services

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Implementing distributed geoscience information
systems using Open GIS Web Services

• Simon Cox
• CSIRO Exploration Mining
• http//www.em.csiro.au

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Outline

• Information Services
• Information Communities
• XML for geoscience
• Service chains

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Information Services

• HTTP is a lot more than web-pages

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Evolution of web-page delivery

• Static webpages
• http//my.big.org/people/fred.html
• URL maps to disk-file
• Dynamically generated webpages
• http//my.big.org/catalogue?item358
• URL maps to a local procedure call
• Each site encodes query differently ? unique UI
• Result only accessible to humans

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Web services

• Information services
• XML(?) packets of re-usable data
• minimal latency
• Computational services
• bigger parameter set
• latency acceptable
• Federated databases
• Service chains?

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Standards for geospatial data

• Open GIS Consortium ISO/TC 211
• Information models and service interfaces

• Service implemented as a set of request-response
  message pairs
• Fine-grained
• Spatial Data Infrastructures

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WFS in detail

• Standard request syntax
• e.g. GetFeature

• Standard response
• FeatureCollection encoded using a GML application
  language

http//wfs.my.big.org SERVICEWFS VERSION1.0.0
REQUESTGetFeaturePROPERTYNAMExmmlcollarLocat
ion,xmmllogsTYPENAMExmmlBoreholeBBOX135.1,
-34.0,135.2,-33.9
ltgmlFeatureCollection gmlidC23"gt
ltgmlboundedBygt lt/gmlboundedBygt
ltgmlfeatureMembersgt ltxmmlBorehole
gmlid"R456"gt ltxmmlcollarLocation
/gt ltxmmllogsgt lt/xmmllogsgt
lt/xmmlBoreholegt
lt/gmlfeatureMembersgt lt/gml FeatureCollectiongt
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Private vs. public schemas

• WFS is a façade to a DB or GIS

• Data-store organised for custodians requirements
• esp. maintenance

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Information Communities

• Meaningful discourse requires shared information
  models

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Information model

• Basic feature model

• to be extended for specific applications

• class name feature-type
• borehole
• mineral occurrence
• gravity measurement
• fault
• attribute association names properties of
  this feature-type

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Information transport

• Serialised form

ltxmmlBorehole gmlid"R456"gt
ltgmldescriptiongtExploration holelt/gmldescription
gt ltgmlnamegtnorth_r_679lt/gmlnamegt
ltxmmlcollarLocationgt ltgmlPoint
srsName"urngalocalGrid68" gmlid"c679"gt
ltgmlposgt ... lt/gmlposgt lt/gmlPointgt
lt/xmmlcollarLocationgt ltxmmlcollarDiameter
uom"m"gt0.15ltxmmlcollarDiametergt ltxmmlshape
xlinkhref"http//my.big.org/borehole_surveys/s67
9"/gt ltxmmllogsgt ltxmmlIntervalLoggt
ltgmlnamegtLithology loglt/gmlnamegt
ltxmmlcategoryList property"lith"

codeSpace"unitcodesgt CANIS FH PL2
PL3 AQ AQL T1 T2 C1 C2 GCWS
lt/xmmlcategoryListgt ...
lt/xmmlIntervalLoggt lt/xmmllogsgt lt/xmmlBorehol
egt

• Based on Geography Markup Language
• element name feature-type
• content properties of this feature-type
• GML is required for WFS compatibility

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Geography Markup Language

• GML 3.0 provides
• Geometry/topologytemporalcoordinate reference
  systems (ISO 19107, 19108, 19111)
• Coverages grids (ISO 19123), Observations,
  Dynamic features, Definitions, Units of
  measure, essential basic datatypes

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Implementing a community language

• 2 aspects to be defined
• The principle elements - in a Feature-type
  catalogue
• formalise using XML Schema
• based on GML to ensure WFS compatibility
• Vocabularies of valid property values several
  methods
• enumerations in XML Schema
• allows validation, but not extensible
• URL instances e.g.
• http//my.big.org/classifications/lithology/komati
  ite
• http//my.big.org/classifications/lithology/greywa
  cke
• offline

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eXploration Mining Markup Language

• Standards-based language for earth sciences
  information

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XMML Feature Catalogue

• Borehole
• Observation (OGC SensorWeb)
• Gravity measurement (GA)
• Geochemistry/Assay result (ADX)
• Geological material (NORTON)
• Geological timescale (IUGS)
• Mineral occurrence (GA)
• Procedure, Project, Station, Specimen, Tenement,
  Instrument (GGIPAC, etc)
• Point, Curve, Surface, Solid with properties
  (Fractal)

• Time-series (ASEG)
• Structural geology elements
• Mine components?
• Finite element model (FLAC, FastFlo)
• Simulation/model state (pmdCRC)
• General coverage, including tensor fields,
  directly from GML

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Design method

• Iterate between XML instances, XML Schema, UML
  model, harmonising with current state of suite of
  schemas
• Adapt existing standard
• e.g. GGIPAC, ASEG
• Private model from dominant data provider
• e.g. Geoscience Australia
• Sponsor requirements
• e.g. Fractal Technologies, CSIRO/pmdCRC, BGS,
  Snowdens/WMC/Newmont
• Consultation with stakeholders
• TWiki

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Deployment requirements

• Develop GML Application Language
• serialisation of community information model
• WFS server-side software
• Easy to configure mapping from private to public
  data models
• Client applications
• desktop software must have WFS client back-end
• applets in standard portals
• Middleware
• data-source catalogues, service registries,
  brokering

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Use community standards at the interface
WFS Server
WFS Client (e.g. visualisation)

• Common encoding interoperability within the
  community

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Project schedule

• Commenced at CSIRO 2000
• Sponsors joined progressively
• MERIWA funded phase concluded June 2003
• Extensions through GGIPAC, pmdCRC, AcQuire
• Maintenance
• OGC schema repository
• OGC RFC late 2003
• Geoscience Australia, British Geological Survey,
  BRGM?
• Submit to IUGS mid 2004