inspire & gml

armasuisseBundesamt für Landestopografie swisstopoKOGIS

INSPIRE & GML

Swiss experiences

20.04.23

2 Bundesamt für Landestopografie swisstopoKOGIS

Content

1. Swiss Testcase: “INSPIRE Admininstrative Units”• From Swiss “INTERLIS XML” to “INSPIRE GML” (XQuery

Transformation)• Deployment on WFS (which software is suitable?)• Accessing data with GIS-Client (QGIS)

2. Some statistics on INSPIRE GML Schemas3. Conclusions

• complex and voluminous documentation• codelists are difficult to handle (XML mechanism do not work)• constraint handling difficult • Clients & Server only support subset of geometry types• gml:AssociationAttributeGroup (xlink) not supported by most tools

4. UML Profiles? Can UML profiles help in handling some of the problems• spatial types• xLink (restricting)

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SWISS ADMIN BOUBNDARIESExample

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INSPIRE Administrative Units- Source Data -Swiss Dataset available for Administrative Units of Switzerland (‘swissboundaries3D’)•data for country, cantons, regions, …

• Unique Identifier• Geometry (Polygons with 3D points and straight

internodials)• Canton-Number (BFS)• Canton-Name• Part of the Canton (exclaves)• Area• Area of contained water-bodies• Inhabitants

•INTERLIS datamodel available•Specific INTERLIS XML encoding of data

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INSPIRE Administrative Units- Source Data -

<swissBOUNDARIES3D_1_1_CH_LV03.TLM_GRENZEN.TLM_BEZIRKSGEBIET TID="55"><UUID>FDA49AE0-D4C8-43EF-9275-0624413C5949</UUID> <Datum_Aenderung>20121203</Datum_Aenderung> <Datum_Erstellung>20121026</Datum_Erstellung> <Erstellung_Jahr>2012</Erstellung_Jahr> <Erstellung_Monat>10</Erstellung_Monat> <Revision_Jahr>2013</Revision_Jahr> <Revision_Monat>1</Revision_Monat> <Grund_Aenderung>verbessert</Grund_Aenderung> <Herkunft>swisstopo</Herkunft> <Herkunft_Jahr>2012</Herkunft_Jahr> <Herkunft_Monat>3</Herkunft_Monat> <Revision_Qualitaet>TLM_GN_Leer</Revision_Qualitaet> <Objektart>Kanton</Objektart> <Shape> <SURFACE> <BOUNDARY> <POLYLINE> <COORD><C1>755108.7</C1><C2>142498.89</C2><C3>2816.24</C3></COORD> … </POLYLINE> </BOUNDARY> </SURFACE> </Shape> <Bezirksnummer>1825</Bezirksnummer> <Bezirksflaeche>119658</Bezirksflaeche> <Bezirk_Teil>0</Bezirk_Teil> <Name>Uri</Name> <Kantonsnummer>18</Kantonsnummer> <ICC>CH</ICC> <Einwohnerzahl>9576</Einwohnerzahl></swissBOUNDARIES3D_1_1_CH_LV03.TLM_GRENZEN.TLM_BEZIRKSGEBIET> ...

Rec.


TRANSFORMATIONFrom Swiss INTERLIS XML Data to INSPIRE GML

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INSPIRE Administrative Units- General Mapping -• Aggregating Input Features

• The source model contains single administrative «areas»

• The target model combines those areas into units

• Transfer of ‘data load’

• Name

• Canton Number

• Generate Geometries

• Source geometry in specific encoding

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INSPIRE Administrative Units- Mapping Problems 1 -• Geometry:

• gml:MultiSurfacePropertyType • what ‘surfaceMembers’ to use? (choice: ‘Polygon’)

• InspireId• localId = UUID• what namespace to use? (choice: http://

www.swisstopo.admin.ch/identifier)• Codelists (difficult to use correctly)

• National Level = ‘2nd Level’ (Information available in INSPIRE Registry - http://inspire.ec.europa.eu/codelist/AdministrativeHierarchyLevel)

• Country Code = ‘CH’ (according to ISO-3166 see ‘Interinstitutional Style

Guide’ http://publications.europa.eu/code/en/en-370100.htm)

What Codelist-URI for ISO-3166? (choice: ‘http://www.inspire- somewhat.eu/pleaseReplace’)

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INSPIRE Administrative Units- Mapping Problems 2 -• Several other required elements

=> lots of xsi:nil=‘true’ andnilReason=‘unknown’

• Very complex structure for simple contente.g. Name (INSPIRE Geographical Name)• Name value nested in:

gn:spelling/gn:SpellingOfName/gn:text• Fixed values for ‘language=de’ and

‘nameStatus=official’• All other required elements: xsi:nil=‘true’ and

nilReason=‘unknown’

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SOFTWARE ISSUESSet-Up of a WFS

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Software Issues- Setting up a deegree WFS -• A test installation is set up with

• deegree services 3.3.7

• transformed INSPIRE data in XML datastore (in memory)

Configuration complex, but not problematic

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Software Issues- Accessing Service with QGIS -• QGIS 2.2.0 with WFS 2.0 extension

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No Access to codelists

Structure is not reflected (flattened)

Attributes not accessible (e.g. units, nill-resons)


Software Issues

• Configuration of Systems is difficult• GML attributes are not accessible with standard GIS

(QGIS)• e.g. nilReason, local, uom

• QGIS cannot handle xLink references (neither attributes nor geometry elements)

• QGIS cannot handle external codelists• Data is flattened with problems

• hierarchy context is lost• empty elements are not displayed• multiple occurrence is badly displayed

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Content

1. Swiss Testcase: “INSPIRE Admininstrative Boundaries”• From Swiss “INTERLIS XML” to “INSPIRE GML” (XQuery

Transformation)• Deployment on WFS (which software is suitable?)• Accessing data with GIS-Client (QGIS representation problems)




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HOW IS GML USED IN INSPIRE APPLICATION SCHEMAS

Geometries, Measures,

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Objects & Features

• Annex I• gml:AbstractObject• gml:AbstractFeature• gml:AbstractFeatureType• gml:AbstractMemberType

• Annex II & III• gml:AbstractGML• gml:AbstractGMLType• gml:AbstractObject• gml:AbstractFeature• gml:AbstractFeatureType• gml:AbstractMemberType

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Geometric

• Annex I• gml:GeometryPropertyType• gml:GeometricPrimitivePropertyType• gml:PointPropertyType• gml:CurvePropertyType• gml:SurfacePropertyType• gml:MultiSurfacePropertyType

• Annex II & III• gml:GeometryPropertyType• gml:GeometricPrimitivePropertyType• gml:PointPropertyType• gml:CurvePropertyType• gml:SurfacePropertyType• gml:MultiCurvePropertyType• gml:MultiSurfacePropertyType• gml:DirectPositionType• gml:PolygonPatch• gml:SolidPropertyType

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Measures

• Annex I• gml:MeasureType• gml:SpeedType• gml:LengthType• gml:AreaType

• Annex II & III• gml:MeasureType• gml:AngleType• gml:AreaType• gml:LengthType• gml:VolumeType• gml:UnitOfMeasureType

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Special

• TIN & Coverages• gml:Tin• gmlcov:AbstractCoverage• gmlcov:AbstractCoverageType• gmlcov:AbstractDiscreteCoverageType• gmlcov:RectifiedGridCoverage• gmlcov:ReferenceableGridCoverage

• Time:• gml:TimeInstantPropertyType• gml:TimePeriodPropertyType• gml:TimePositionType• gml:TimePrimitivePropertyType• gml:AbstractTimeObject

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Special

• gml:AbstractMetadataPropertyType

• gml:AssociationAttributeGroup

• gml:OwnershipAttributeGroup

• gml:FeaturePropertyType

• gml:CodeType

• gml:NilReasonType

• gml:ReferenceType

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Content






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QUESTIONS, PROBLEMS, OPEN ISSUES

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Documentation

• Documentation is highly complex and voluminous• Required Information for data generation:

• UML Model/Data Specification Document of theme and all related themes

• INSPIRE Registry• GML Application Schemes• GML Specification• Documentation of referred Codelists

=> Hands-On, Samples, Best-Practises, .. would really help

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External Codelists

• External Codes are difficult to handle

• Location for suggested Codelists are not visible in application schema or data specification

• No GIS tool supports external vocabularies

• XML validation is not respecting values

=> ???

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Constraints

• Several OCL (esp. on restricting generic data types) are not reflected in application schemas

• e.g. OCL Constraint on Cadastral Parcel

• resulting GML application schema

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/* geometry shall be GM_Surface or GM_MultiSurface */inv: geometry.oclIsKindOf(GM_Surface) or geometry.oclIsKindOf(GM_MultiSurface)

<element name="geometry" type="gml:GeometryPropertyType"> <annotation> <documentation>As much as possible, the geometry should be a single area.</documentation> </annotation></element>


Constraints 2

• Constraints only defined in OCL are difficult to find and understand

• Constraints cannot be validated for GML data

=> ???

=> GML Profiles can partly reduce the available data types

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Geometric Types

GIS tools only support limited geometric types

•Point, Curve, Polygon (with LineStrings, Arcs)

•Multipoint, Multicurve, Multisurface (with Polygons)

=> GML Profile similar to Simple Features Profile

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XLink (‘inLineOrByReference’)

• In INSPIRE most feature-attributes can be encoded ‘inline’ or ‘by-reference’

• Common GIS (QGIS) mostly only support ‘inline’ encoding – xLink references can hardly be resolved

=> GML Profiles might restrict the usage of ‘by-reference’ attributes

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Content






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GML PROFILES FOR INSPIRE?Reduce the complexity

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GML Profiles for INSPIRE?

• Would GML profiles help(similar to GML Simple Features – but without ‘by-reference’ attributes)?

• Must we define more than one profile?

• For simple (e.g. administrative boundaries, protected sites, …)

• Specific themes (e.g. buildings, geology)

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