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Standards and the US National Spatial Data
Infrastructure
Improving access to geospatial information
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OverviewFGDC and GIS StandardsDivision of labor in standardization
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FGDC ObjectivesTo promote access to and usage of digital geospatial information of national and local valueTo improve discovery of and public access to federal geospatial data resourcesTo reduce duplication of effort among public sector organizations developing geospatial data
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FGDC and StandardsFGDC provides a public forum for the development of content-based standards for general or information community useExamples: Content standard for digital
geospatial metadata Framework data standards
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Endorsement of External Standards
In 2010, the FGDC endorsed a set of 64 external geospatial standards as a reference set for community use Derived from a much longer list of DoD IT Standards Registry (DISR) Point of collaboration with the Geospatial-Intelligence Standards Working Group (GWG)
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ISO Standards (TC 211)FGDC participates in ANSI/ISO standardization under ISO TC-211Some areas of participation: Metadata content standard Services Encoding Data Quality
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FGDC and OGCFGDC participates in the Open Geospatial Consortium for the development of common implementation specifications to improve access to spatial informationUsers benefit from vendor support of information access specifications and integration of solutions into GIS workflow
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OGC SpecificationsDesigning implementation solutions for discovery through Catalog ServicesApproved: Simple Features SQL, KML, Web Map Server Specification, Geography Markup Language (GML), Catalog Services Specification, Web Coverage Services, Web Feature Services, Sensor Observation ServiceGoing beyond Simple Features to raster (coverage) services and eventually distributed GIS
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GIS Standards TurfISO TC-211 is focused on the abstract specifications, design framework and international political consensus (what)National standards support the development of community content standards (who, why)OGC specializes in extending the abstract model into implementation specifications (how)
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SDIs and Standards Advocacy
OpenGIS OpenGIS Consortium, W3CConsortium, W3C
Software interfaces(ImplementationSpecifications)
ISO TC 211ISO TC 211
Foundations forimplementation.
(Abstract standards)
NationalNationalStandardsStandards
Content standards,Authority for data
Endorsed practices and specification
s
SDISDI
OtherNSDIs
RegionalSDI Coordination
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are derived for each
APIAPI
API
API
API
UI
MetadataDB/Index
MetadataDB/Index
Data CatalogService
Data CatalogService
GEOdataAccessService
GEOdataAccessService
Web MappingService
Web MappingService
ServiceRegistry/Catalog
ServiceRegistry/Catalog
CatalogClient
CatalogClient
Web ClientWeb Client
Data/FileManagement
System
Data/FileManagement
System
OtherService
OtherService
Symbols
currentcurrent
InterfaceUI
Software/Service
Information
SpatialData
SpatialData
MetadataMetadata
Function
are derived
from
are loadedto or
stored in
is exposedto the Internet
through a
MetadataMetadata stores service info
performs lookupto grab operation
signatures
queries
stored in
is exposedto the Internet
through a
may reference instances
may be coupled
to or integrated
with
plannedplanned
API
draws layers from
makesmapsfrom
UI
UI
managedthrough
managedthrough
GatewayGateway
interacts with
distributes to and collates
from multiple
ThesaurusThesaurus
GazetteerGazetteer
enhancesquerywith
enhancesquerywith
UI
feedsserver info
to
1. builds query screens for2. submits queries/requests to3. returns search responses
1 2 3
UI
enter/update
UI
managedthrough
may senddata to
now: planned.:
managedthrough
API
providesapplication
accessthrough
APIsynchronize
Application Client
Application Client
interacts withSDI Interaction
Diagramrevised [email protected]
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Standards are monolithic yet interdependent
XMLdeployed as
ISOSpatial
Schema
harmonized with
HTTP
used fortransport
GML3.0
may returnWFS1.0
XMLSchema
validates against
validates
UML
expressed in
transformable to
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Framework ThemesThemes providing the core, most commonly used set of base data are known as Framework Data: Geodetic Control, Orthoimagery, Elevation and Bathymetry, Transportation, Hydrography, Cadastral, and Governmental Units.
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Additional Data
Geographic names (toponymy) layerLand cover/vegetation/wetlandsCultural and Demographic StatisticsBuildings and FacilitiesNatural hazardsSoils and GeologyUtility distribution networks
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Framework StandardsIn 2008, the FGDC published eleven Framework standardsIncluded an abstract model (in UML) and had companion XML schema files
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6. Forward Draft for6. Forward Draft forReview and ApprovalReview and Approval
Design Process
Modeling AdvisoryTeam (Team of Experts)
1. Requirements1. Requirements
2. Design2. Design
Community
3. Review3. Review
Application-Neutral
Content Model
Encoding(XML)
4. Comments4. Comments
5. Refine5. Refine
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Conceptual Model
A conceptual or logical design of the information that preserves the native groupings of the dataIs implementation- and software-independent to provide a stable base for current and future implementationsDescribes graphically and with narrative the design assumptions and conditionsCurrently expressed using the Unified Modeling Language (UML)
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What is UML?Unified Modeling LanguageUML is an industry standard language for visualizing, specifying, constructing, and documenting artifacts of a software-intensive systemPlatform-neutral environment for abstract modeling of data and processesAdopted as the Conceptual Schema Language for ISO TC 211
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UML Diagrams
Use CaseDiagramsUse Case
DiagramsUse CaseDiagrams
ScenarioDiagramsScenario
DiagramsCollaborationDiagrams
StateDiagramsState
DiagramsComponentDiagrams
ComponentDiagramsComponent
DiagramsDeploymentDiagrams
StateDiagramsState
DiagramsObjectDiagrams
ScenarioDiagramsScenario
DiagramsStatechartDiagrams
Use CaseDiagramsUse Case
DiagramsSequenceDiagrams
StateDiagramsState
DiagramsClassDiagrams
ActivityDiagrams
Models
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Class DiagramCaptures the ‘vocabulary’ of a systemBuilt and refined throughout developmentPurpose Name and model concepts in the system Specify collaborations Specify logical database schemas
Developed by analysts, designers, and implementers
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UML Class Diagram
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The UMLUseful for diagramming systems, objects, and relationshipsMany diagrammatic conventionsMany ways to diagram the same thingCan serialize the UML as XML (XMI)CASE tools or transforming programs can create implementation bindingsFGDC is hosting a UML-to-GML transform program for convert UML into XML Schema
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UML per Rational Rose
UMLIntegrated
DevelopmentEnvironment
UserInterface
OracleTable
Schema
JavaProgram
Code
conten
t
proceduresand structures
XMLSchema
Document
structures
ConceptualModels
Implementations
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Start ModelingReview existing models from FGDC and The National Map efforts and adapt/adopt them if possibleIdentify theme experts who are either producers or users of digital geographic dataApply modeling expertise to work with the experts interactively to build model
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Framework Data ModelingBased on provider and consumer requirements for GIS and mapping, focus on a specific theme of informationConvened a group of experts with modeling support and have them bring any relevant systems designs or requirements documentsBuilt models that support a common, not universal, set of needsPublish model and narrative in a standard
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Common Modeling Baseline
Feature types (classes) includedUnique feature identifier systemBasic attributesControlled vocabulary, codes, authoritiesValid at a range of scales and resolutionsMultiple representations of same features possible
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Feature CatalogOne first step toward developing a conceptual model of geographic information is to construct a Feature CatalogFeature Catalog includes: Feature types, definitions Attributes, definitions, data types Domains, expected values and types
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Catalog as Abstract Model
Feature Catalog describes what information is included in a given data theme and what properties and values are stored thereA feature catalog is not an implementation model but can, with rules, be used to create one or more implementation modelsImplementation guidance supplements abstract or conceptual models
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Example UML Model(example excerpt from the hydro model, prior to face-to-face session in November)
Metadata is at a collection level; for example it will apply to ISO, FGDC etc.
Metadata
Time of samplePOCetc.
Dataset
Feature Name
Permanent Feature IDGNIS-IDname
HydroLine
Reach IDFrom positionTo PositionLength
HydroArea
Elevation of areaWater surface basis heightArea of featureRegion ID
Hydrography
Permanent Feature IDFeature Type CodeFeature QualifierGeometry : Geometry Type EnumerationSource Scale Denominator : Integer
HydroPoint
ReachIDPeriodicity : Periodicity Type EnumerationCartographic feature type codeHydrographic feature code
describedBy
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Example Tabular Description
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Going from the Abstract to Implementation
Conceptual modeling yields the natural organization of the data but not a specific implementationFor interoperability in the exchange of data, an agreement on encoding and format is requiredCASE tools and scripts can convert UML designs into specific implementation schemas
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Application SchemaName for the rules that define the content, relationships, attributes, domain values and constraints in a specific implementation environmentUML may be converted into XMI to load the model design into a different modeling softwareUML may be converted to an XML/GML Schema Document
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Content + Format
Format A
Data
ConceptualData
Model
Implementationmodel/schema for Format A
encoding
validation
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Creating a Standard
A standard facilitates interoperability if it includes both the conceptual data model and one or more implementation annexes with specific guidance for content validation
ConceptualData
Model
Narrative with context,obligation, examples
Data Content and Exchange Standard
ImplementationSchemas
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Framework Standard Outline
IntroductionScope and ContextData Content Model in UMLDescriptive table and narrativeAnnex: Encoding using XML (GML 3.0)
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Geospatial ServicesIncreasingly geospatial data can be accessed in real-time over local area networks and the Internet as if it were local dataMultiple organizations can benefit from the data being staged and maintained once and used many timesDesktop software and portals can use these services over the Web
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Framework Interoperability Pilot for Transportation
OpenGIS Consortium (OGC) is assisting in modeling process to define proper UML that conforms to ISO rules and can be implemented as GMLContract with OGC members to implement Web Feature Services to extend multiple available data systems (U.S. and Canada)Implement a Web client that can display and query multiple Framework data sources based on the common data modelApproach to be followed for other themes
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Establish WFS on agreed content nationwide
MissionSystem AWeb Feature
Browser/Client Application
MissionSystem B
Native FormatGML
(XML)
WFS
WFS
translationutilities
BprivateschemaPpublic
schematransformation
rules
