INSPIRE DS Stream Data Specification Elevation v2.0

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INSPIRE DS StreamINSPIRE DS Stream

Data Specification Data Specification ElevationElevation v2.0 v2.0

Jordi Escriu Paradell - TWG EL EditorInstitut Cartogràfic de Catalunya (ICC)

INSPIRE Conference 2011Edinburgh, 29th June -1st July 2011

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This presentationThis presentation

TWG Elevation INSPIRE Data Specification Elevation (v2.0)

Overview Elevation theme Reference materials Scope

Results and achievements Key aspects UML Model

Open issues

INSPIRE DS Stream – Data Specification Elevation v2.0 2

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End Nov 2010 – Delivery of DS EL v1

TWG TWG ElevationElevation

Michael Hovenbitzer (Facilitator)

Jordi Escriu Paradell (Editor)

Chris Howlett

Dave Capstick

Eduardo González

Gyula Iván

Lee Brinton

Lynne Allan

Rogier Broekman

Tim Kearns

Veijo Pätynen

Vincent Donato

Zdzislaw Kurczyński

Katalin Tóth (EC- JRC contact point)


I II III IV

2012

2010

2011

II III IV I II III

May 2010 – TWG EL Kick-off Meeting Frankfurt

June 2011 – Delivery of DS EL v2

Nov 2010 – TWG EL Meeting Warsaw

March 2011 – TWG EL Meeting Barcelona

April 2012 – Delivery of DS EL v3

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ElevationElevation theme theme

• Definition

“Digital elevation models for land, ice and ocean surface. Includes terrestrial elevation, bathymetry and shoreline.” [INSPIRE Directive, 2007/2/EC]

• Description

“The theme includes:

Terrestrial elevation (namely land-elevation), represented as:– Digital Terrain Models (DTM) describing the three-dimensional shape of the

Earth’s surface (ground surface topography).– Digital Surface Models (DSM) specifying the three dimensional geometry of

every feature on the ground, for example vegetation, buildings and bridges.

Bathymetry data, e.g. a gridded sea floor model”[Adapted from INSPIRE Feature Concept Dictionary]


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ElevationElevation theme theme

• Relationships with other INSPIRE themes

– Geographical names – Summits, mountain passes, singular spots

– Hydrography / Administrative Units – Data consistency

– Sea Regions – Shoreline (Coastline)

– Buildings / Utility and governmental services / others…

• Properties storing absolute elevations

• Identification of the Vertical CRS to which these are referenced

– Orthoimagery (& others using grids)

• Modelling of Grids as coverages

– Use cases of many themes use Elevation data as input for spatial analyses (EL present in 11 use cases)


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Reference materialsReference materials

Reference documents

• 36 received and analysed

User requirements survey

• 44 received• 4 Key use cases selected

– Flooding– Orthoimagery production– Safety in maritime and hydrographic navigation– Elevation mapping


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DS ScopeDS Scope


In the scopeContent

•Land elevations:Absolute gravity-related heights

•BathymetrySea and inland water bodies

depths

Modelling of surfaces

•2.5-D, only one value per planimetric position•Either a Digital Terrain Model (DTM) or a Digital Surface Model (DSM)

Data representations

•Vector data (2-D and 3-D geometries)•Gridded data (coverages)•TIN data

Out of the scope

•Measurement procedures from which elevation properties are gathered

•Bathymetry of river courses

•CoastlineINSPIRE Data

Specifications on Sea Regions, ‘CoastLine’ Feature type

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Key aspects (I)Key aspects (I)

• Homogenous / Integrated approach to– Land elevation and bathymetry data (elevation properties)– Representation of different surfaces: DTM, DSM– Different spatial representation forms: Vector, Grid, TIN

• Identifier management– Unique identifiers mandated for vector spatial objects, grid coverages and TIN structures

• Object life-cycle information (voidable)– beginLifespanVersion / endLifespanVersion

• Coordinate Reference Systems (requirements / recommendations)

Identification of the Vertical CRS is needed! - Mechanism provided in the EL model


Geographical Scope CRS to be used

Inside ETRS89 scope(continental Europe)

ETRS89-GRS80 recommendedHeights: EVRS mandated (IR Data Interoperability)

Outside ETRS89 scope(overseas territories)

MS to decide and identifyHeights: Earth Gravitational Model (EGM Version 2008) recommended

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Key aspects (II)Key aspects (II)

• Cross-border interoperability (Grids):– Main Issues:

• MS Data is stored using national grids (different CRSs and map projections) – This makes necessary to perform transformations with their inherent quality lose.

• National grids uses different grid cell alignment rules.

– Possible solution to fix these issues• Provide Elevation data using a Common European / Global Grid.

– Existing common grid• Grid_ETRS89-LAEA, established as the multipurpose Pan-European standard by the IR on Data Interoperability

(Annex I - DS on Geographical Grid Systems).• Based on the ETRS89 Lambert Azimuthal Equal Area CRS (ETRS89-LAEA)• Main purpose: Framework for spatial analysis and reporting• Not appropriate for Elevation data

– PROPOSAL: European Common Grid for Raster Data (Grid_ETRS89-GRS80)• Hierarchical grid based on ETRS89-GRS80 geodetic coordinates• Common set of rules assuring aggregation of grid cells (grid origin, grid cell reference point)• Recommended for provision of EL and OI data aimed at cross-border purposes (DS Annex C)• Aligned with the IR (Section 2.2.2): Other theme-specific grids may be specified

Data based on national grids is totally valid within their geographical scope!


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UML Model - StructureUML Model - Structure


INSPIRE Generic Conceptual Model D2.5

Coverages (Domain and Range) App. Schema

ISOStandards

ISOStandards

Elevation - BaseApp. Schema

Elevation – Vector ElementsApp. Schema

Elevation - CoveragesApp. Schema

Elevation - TINApp. Schema

INSPIRE ElevationData Product Specification

D2.8.II.1

INSPIRE Directive

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UML Model – Application schemasUML Model – Application schemas


Describing…

Basic classes ‘ElevationDataSet’ Generic components

Common types

[Data types] Vertical CRS identification

‘ElevationCRSReference’

[Code lists & enumerations] Elevation property type

‘height’ / ‘depth’ Surface type

‘DTM’ / ‘DSM’

Ele

vati

on

- B

ase

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Describing…

Generic abstract class ‘ElevationVectorObject’

Specialized features types Points

‘SpotHeight’, ‘SpotDepth’ Lines

‘ContourLine’, ‘DepthContour’ Auxiliary objects

‘BreakLine’, ‘VoidArea’, ‘IsolatedArea'

Ele

vati

on

– V

ecto

r E

lem

ents

Points LinesSpot Height

Spot DepthContour

LineDepth

Contour

Break Line

Void Area

Isolated Area Elevation

Vector Object

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Describing…

Main class ‘ElevationGridCoverage’

Elevation property / Surface ‘height’ / ‘depth’ ‘DTM’ / ‘DSM’

Conformity to Generic Conceptual Model (GCM)

• ISO 19123:2005 – Coverages geometry and functions

• Current draft of WCS 2.0

Ele

vati

on

– C

ove

rag

es (

Gri

ds)

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Describing…

Main class ‘ElevationTIN’

Elevation property / Surface

‘height’ / ‘depth’ ‘DTM’ / ‘DSM’

Conformity to ISO 19107:2003 –

Spatial Schema

Type ‘GM_Tin’

Ele

vati

on

- T

IN

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Open issuesOpen issues

• Bathymetry of river courses– Not in the current scope of the DS – Needed for relevant use cases like e.g. safety of inland navigation?

• Cross-theme data consistency– Not clear how to achieve positional / logical consistency between data from different INSPIRE themes.

• Elevation Vector and TIN cross-border data consistency– Must be further investigated by the TWG.

• Grid coverage data aggregation– An integrated approach with TWG-OI is needed.

• Requirements / recommendations on depth measurement – Under discussion– For the vertical component measuring the depth of the sea floor, where there is an appreciable tidal range, the Lowest

Astronomical Tide shall? be used as reference surface. In marine areas without an appreciable tidal range, in open oceans and effectively in waters that are deeper than 200 m, the depth of the sea floor shall? be referenced to the Mean Sea Level.

– For the vertical component measuring depths above the sea floor in the free ocean, barometric pressure shall be used .

• Data quality– Target results for DQ measures and recommended evaluation procedures.

• Metadata– Mandatory / Optional theme-specific metadata elements - Under discussion. – Guidance on specific MD elements – e.g. template for Lineage


Looking for feedback fro

m the

Consultation & Testing Phase!

16INSPIRE DS Stream – Data Specification Elevation v2.0 16

Thank you for your attention!!Thank you for your attention!!

[email protected]@jrc.ec.europa.eu

INSPIRE DS Stream Data Specification Elevation v2.0

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