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Australian Geofabric
implementation of HY_Features
connecting observations, monitoring sites and hydrological
features using Linked Data
Hydro DWG Workshop, Quebec
Rob Atkinson, CSIRO Land and Water
Tony Boston, Australian Bureau of Meteorology
June 2013
Overview
• HY_Features scope and benefits
• Implementation within the Australian Hydrological
Geospatial Fabric (Geofabric)
– Geofabric development
– Methodology and key design decisions
– Connecting observations, monitoring sites and hydrological features
using linked data
• Demo
• Summary
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Scope of HY_Features
• Concerns of the WMO Commission for Hydrology (CHy)
– interoperability of observing systems relevant for hydrology
– exchange of hydrological data and information on a global scale
– sharing of data models and patterns in use in the hydrology domain
• Abstraction of the real-world hydrology phenomena
–
–
–
–
–
Features which are the object of study / reporting in hydrology
... that have properties usually observed in hydrology
... that are physically / logically connected in networks
... that have names in cultural, political and historical context
... that are assigned generally applicable characteristics
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Benefits of HY_Features
• A common hydrologic feature model
– Common terminology: definitions based on WMO standards
(International Glossary of Hydrology)
– Supports multiple representations of features at different scales
• Its implementation would support global linkage to
hydrological features using standard patterns
– River basins and aquifers are hydrological units of study,
management and reporting
• Show me all the river basins greater than area W
• What is the definition of river basin X or aquifer Y?
• What are gauging stations related to river basin Z?
• And allow development of common tools for discovery,
access and sharing of hydrologic information
– Realising the vision of linked data
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What is the Australian Hydrological
Geospatial Fabric (Geofabric)?
1.
2.
3.
4.
5.
Evolving and consistent spatial data product …
that identifies important water features in the landscape …
as well as the connections between these features …
and supports multiple representations.
It is a framework to underpin Australia’s water information
activities
6. Collaboratively developed by the Bureau of Meteorology,
CSIRO, Geoscience Australia and ANU
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1. Evolving and consistent
spatial data products
Geofabric products
Phased release plan
1. Geofabric Phase 1 V1.0
- released 2010
2. Geofabric Phase 2 V2.0
- released 2011
3. Geofabric Phase 2 V2.1
- released 2012
4. Geofabric Phase 3
- beta release 2013
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Reporting Regions
Reporting
Catchments
Catchments
Network
Cartography
Groundwater
2. Identification of important
water features
River confluences
River outflow to sea
Inland sink
Monitored features
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Image Source:
Bing Maps
3. Connections between
water features
Connected features
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with different representations
4. Supporting multiple
representations of water features
Complex vs Simple Geography
Complex vs Simple Topology
Contracted Node
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5. To underpin Australia’s
water information activities
Visualisation and mapping
Hydrological modelling
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Catchment contributing areas
Water reporting
Geofabric product generation
Source: CSIRO WIRADA
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Geofabric Web Services
• For each of the 34 features
within six Geofabric products
there is:
– a WMS
– a Simple Feature WFS
– a Complex Feature WFS using
app-schema
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Multiple (scale) representations
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Geofabric V2.1 product relationships
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Mapping HY_Features to the Geofabric
Model Mapping Diagram
«FeatureType»
HY_Catchment::
HY_CatchmentArea
«FeatureType»
HY_Catchment::
HY_CatchmentRepresentation
+
+
+shape
1
+shape
1
«representsAttribute»
area :Area [0..1]
shape :GM_Surface [0..1]
«mappingClass»
AHGFContractedCatchment
1
«realisedObject»
0..*
«mapsTo»
1
«realisedObject»
+representedCatchment
«FeatureType»
AHGF_HR_Catchments::AHGFContractedCatchment
«property»
+ AHGFFType :AHGFContractedCatchmentType
1 + conNodeID :Integer
+ hydroID :Integer
+ shape :GM_MultiSurface
+drains
+outfall
1
+drains
0..*
ContractedCatchmentDrainsToLink
1
«representsConnector»
HY_HydroFeature
«FeatureType»
HY_Catchment::HY_Basin
«FeatureTyp...
HY_Catchment::
HY_Catchment
+
1
code :ScopedName [0..1]
1
+code
«mappingClass»
AHGFLink
«realisedObject»
«representsConnector»
+pointOfOutflow
0..*
«FeatureType»
AHGF_HR_Catchments::AHGFLink
1
+fromNode
1 «mapsTo»
+toNode
«representsConnector»
0..*
+drainedBy
1
+hydroID
«representsAttribute»
1
+pointOfInflow
+contributingBasin
1..*
«RelationshipClass»
+pointOfOutflow
«property»
1 + fromConNodeID :Integer
+ toConNodeID :Integer
+ flowDir :HydroFlowDirections
+ hydroID :Integer
+ shape :GM_Curve
NodeDrainsContractedCatchment
«RelationshipClass»
+receivingBasin
+pointOfOutflow
1
0..1
+pointOfInflow
+fromNode
«FeatureTyp...
HY_Catchment:: 1
HY_Outfall
+id()
«realisedObject»
1
«mappingClass»
AHGFNode
+nextDownID
«representsAttribute»
+position.relativePosition.referencePoint.refPoint
«representsAttribute»
1
+position
+position
1
«FeatureType»
HY_Riv erPositioningSystem::HY_IndirectPosition
+
+
+referencePoint
distanceToRefPoint :HY_DistanceToRefPoint [0..1]
relativePosition :HY_RelativePosition [0..1]
1..*
«FeatureType»
HY_Catchment::HY_ReferencePoint
+
+
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1..*
+outfall 0..*
+conNodeId
+receivingBasin.pointOfOutflow
0..1
+toNode
«FeatureType»
AHGF_HR_Catchments::AHGFNode
«representsAttribute»
+networkLocation
1..*
refPoint :GM_Point [0..1]
refPointType :HY_RefPointType [0..1]
1
1
«mapsTo»
«property»
+ AHGFFType :AHGFNetworkNodeType
+ conLevel :Integer
1 + conNodeID :Integer
+ hydroID :Integer [0..1]
+ mapNodeID :Integer [0..1]
+ nextDownID :Integer [0..1]
+ position :GM_Point
+ textNote :CharacterString [0..1]
Geofabric Hydrology Reporting Catchments
Stream Catchment
Stream Network
Contracted Catchment
Contracted
Catchments,
Nodes and Links
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River Regions & Drainage
Division
Australian Catchment Boundaries
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Geofabric Practice
Requirements
Other
products
Conceptual
Model
Product
Impleme
ntation
Product
Model
HY_Features
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AHGF Concepts
XSD
Map
Services
ID
Link
Connecting observations, monitoring sites and
hydrological features using linked data
• Linking related data requires knowing what references
mean
• Identifiers must be bound to well-known semantics (what
type of thing)
• Binding to a specific data product has issues:
–
–
–
–
–
Not portable (don’t do this in standards!)
May not be best representation for user
Fragile (systems change)
Tempting because we probably understand real data....
And a conceptual model not always available
• Enter HY_Features
– A common hydrological feature model independent of scale and
implementation
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Linked data and the Geofabric
Application (Online or Desktop)
http://id.unsdis/id/catchment/567 Identifier Architecture
representations
Basic properties provenance
URL: spatial data access
URL: observation data archive access
Data Marts
Transactions
URL: live data access
Services
Observation
Archive
(Data Warehouse)
URL: virtual data product
Services
WF
S
WC
S
Spatial
databases
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Sensor Web (image OGC 2006)
Computational
Models
Spatial Data Infrastructure
Contracted nodes and catchments
Geofabric Core Hydrology Products
Geofabric Constrained Views
(Core ‘contracted’ & ‘non-contracted’ nodes, Nn;
Contracted
Non-contracted
Core catchment boundaries, Cn)
C3
C2
N4
‘Contracted’ nodes
Persistent identifiers for and connections between nodes in
hydrological network
across multiple representations
Geometry 1
Geometry 2
Complex lines and Simple line
polygons
N2
Topology 1
St
r
Fl eam
ow
C3
CC
C2 5 4
C3
`
`
C1
S1
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C11
C4
C5
S1
N1
X=10, Y=3
N1
C12
C2
`
N2
X=14, Y= 4
N11
C1
Topology 2
`
N3
N1
N2
Monitoring point
(Ghost node)
Catchments represented as multiple
geometries & topologies
N2
`
N3
`
C4
`
N2
`
S1
C2
Geometry
Topology
C5
C3
C1
N1
N3
C21
N2
C1
C1
S1
C22
Waterbody
nodes
N21
N1
Streams represented as multiple
geometries & topologies
N6
C23
N22
C2
N3
C24
(Head node)
N23
N5
N1
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Multiple hydrological representations
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Of course the reality is quite messy...
Many network nodes mapped to single logical node...
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Semantics (1)
•
•
•
•
That messiness is inherent
Complex
Handled in the conceptual model
HY_Features used to describe how Geofabric nodes fit
together
• Initially through design...
– Next step UML model mappings
– OWL ontologies so we can query over relationships
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Semantics (2)
Waterbody
shape:GM_Polygon
Dam
area:GM_Polygon
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CSIRO. UN Gazetteer - Common Semantic Framework for
the UNSDI
Identifiers at work…
http://water.bom.gov.au/waterstorage/awris/index.html#urn:bom.gov.au:awris:common:codelist:feature:lakepieman
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Identifiers
• This is the “tricky part”
• Lets start with the practical implication…
Catchment
ExtractionRate
Storage
1123343
730
300
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Catchment
Boundary
Area
Geometry
1123343
33535.4
151.3344,35.330…….
“Distributed” references
Catchment
ExtractionRate
Storage
1123343
730
300
How to ask for this entity
Internet
How to deliver this entity
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Catchment
Boundary
Area
Geometry
1123343
33535.4
151.3344,-35.330…….
Hydrological Referencing
• Linking hydrological data requires common
semantics
– Observations apply to what?
– How are these objects hydrologically connected?
• Semantics of place
– Talking about the same hydrological context
• “The catchment of the Darling River”
• Hydrologic referencing
– Hydrologic references more explicit that spatial
coordinates
– Names are specific, if we share understanding
– Need to “dereference” names/ids to find hydrologic
context.
– Multiple products, multiple representations, same ids!
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Unstable Identifier Behaviour
URL for a service
http://bom.gov.au/ahgf/250K/wfs?featuretype=ahgf_catchment&id=213343
Data Product Feature Type
http://bom.gov.au : organisation name or custodianship changes
/ahgf/ : service name or dataset, or something else?
/250K : one view
/wfs? : one service (+ version!)
featuretype=ahgf_catchment : what if we want to add attributes or change
model?
&id=213343 : is local identifier stable or database row id?
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Separation of concerns
See http://web.archive.org/web/20130411044033/http://thismodel.posterous.com/cool-uris-and-geographic-resources
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Multiple Resources
HY_Basin common model
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One URI, many resources
• http://115.146.86.108/id/geo/ahgf_hrc/100862
– Get an index of resources + HY_Basin model view
• ID?_view=ahgf:AHGFContractedCatchment&_format=g
ml
• Get HR_Catchments product in GML
• ID?_view=alternates
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Presentation title | Presenter name | Page 33
Generalised Deployment Model
Application Architecture
AWRIS
GIS
HTML Web
Identifiers have a discoverable set of available resources
Identifier Architecture
LID (Linked Data Identifier)
These components deliver these type of information resources
PIDSVC
Resource list
Item
Delivery Architecture
Services
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Download
Workflow
http://water.bom.gov.au/waterstorage/awris/#urn:bom.gov.au:awris:common:codelist:feature
:arthurslake
Definition derived from conceptual model.
Linkages can be made to related concepts...
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Summary
• Conceptual model allows us to have “top level” identifiers
• HY_Features schema provides basic info about top level
object
• Linked Data approach
• Multiple representations
• AHGF may be delivered by
–
–
–
–
Product models (AHGF carto etc)
And HY_Features model
Registered URL ids using data model from HY_Features
alternative data products may evolve and be linked to this
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Take-home...
• Be careful not to overspecify references to specific
information resources.
• HY_Features is target for relationships in standards
– Fix and/or extend if necessary!
• Semantic Web (Ontology) probably best way to traverse
relationships
– Participation and review welcome.
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CSIRO Land and Water
Rob Atkinson
Principal Investigator
Interoperable Information
Systems
Bureau of Meteorology
Tony Boston
Branch Head
Climate and Water Data
Phone: +61 419 202 973
Email: rob.atkinson@csiro.au
Web: www.csiro.au
Phone: +61 2 6232 3503
Email: t.boston@bom.gov.au
Web: www.bom.gov.au
Thank you
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