GML encoding of NADM C1

Connecting geosciences to international standards

Eric Boisvert (GSC)Bruce R. Johnson (USGS)Boyan Brodaric (GSC)Simon Cox (CSIRO)

What is GML ? Geography Markup Language XML encoding of ISO standard for

representation of geographic features Building blocks, providing…

Feature model Points, lines, polygons (geometries) Projection definitions Dictionary structures Topology, Time, and more..

What is GML ? GML by itself has little use Need to define a GML application Extend the provided building blocks

and assign domain (community) specific meaning. gml:_GML

gml:_Feature

gml:_GML

gml:_Geometry

gml:_PropertyValue

Street

Why GML ? International standard (Open GIS

Consortium) Opens the possibility to connect with

other communities WFS (Web Feature Service)

Can be used with GML enabled tools

Why GML ?

GML client

NADM-GML

XMML-GML

NADM-GML

USGS WFS

WFSGSC

Etc. WFS

inte

rnet

USGS schema

GSC schema

other schema

inte

rnet

GML is XML Uses XML to define the building blocks Defined with standard XML Schema XML Schema is then used to extend GML Constraints and restrictions defined the

same way in all XML Schemas GML document must validate against an

XML Schema (GML Schema + domain specific Schema)

GML is not any XML GML has rules (conceptual model) Features must derive from core GML

features GML also has syntax rules Class->property->Class->property Mandatory ids Provides ‘design patterns’

Example

<app:RoadSegment gml:id= "RS1">

<app:name>Handbury Road North</app:name>

<gml:centerLineOf>

<gml:LineString gml:id="L1">

<gml:posList>1 2 2 3 3 4 4 0</gml:posList>

</gml:LineString>

</gml:centerlineOf>

<app:numberOfLanes>2</app:numberOfLanes>

<app:surfaceType>Asphalt</app:surfaceType>

</app:RoadSegment>

Mandatory ID

Features have 0 or more

geometries

RoadSegment

- name: string- numberOfLane: int- surfaceType: string

gml:_GML

gml:_Geometry

0..*

+centerLineOf

pro

pert

ies

Example<app:RoadSegment gml:id= "RS1">

<app:name>Handbury Road North</app:name>

<gml:centerLineOf href= "#L1" />

<app:numberOfLanes>2</app:numberOfLanes>

<app:surfaceType>Asphalt</app:surfaceType>

</app:RoadSegment>

…

…

<gml:LineString gml:id="L1">

<gml:posList>1 2 2 3 3 4 4 0</gml:posList>

</gml:LineString>

options

Encoding NADM C1 in GML Start from conceptual model Create a GML friendly

implementation model in UML Turn association classes into ‘bridge’

classes Define which elements can contain

which other elements Define properties and name them

{Must be part of current CM}

_CompoundMaterial

- consolidationDegree: string

Mineral OrganicMaterial Void

InorganicFluid

Rock UnconsolidatedMaterial

Glass

EMConstituent

- proportion: double- emcRole: string

GeologicRelation

0..1

+emFabric

0..*

0..*

1

1 1

+emConstituentMaterial

1..* +emConstituentProperty

1

_GeologicFeature

_EarthMaterial

- metamorphicGrade: string- color: string

0..*

0..*

+emcRelation

Con

cep

tual

GM

L Frie

nd

ly

Fabric

- pervasiveness: string

_GeologicFeature

_EarthMaterial

- metamorphicGrade: string- color: string

0..*

_CompoundMaterial

- consolidationDegree: string

0..1

+emFabric

Fabric

- pervasiveness: string

Rock

_GeologicEvent

Genesis

0..1+emGenesis

0..*

EMConstituent

- proportion: double- emcRole: string

+emConstituentProperty

1..*

1

+emConstituentMaterial

International effort GML encoding is done within an

international effort to improve interoperability of geoscience

First meeting in Edinburgh (Nov. 2003)

Next meeting Florence (August 2004)

Testbed planned

Conclusion Most difficult part is to define a

design pattern : how to resolve problem consistently

Excellent review process for the conceptual model : raised several issues

Questions ?