data specification elevation v2 · 2011-07-13 · data specification elevation v2.0 jordi escriu...

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INSPIRE DS Stream

Data Specification Elevation v2.0

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

INSPIRE Conference 2011

Edinburgh, 29th June -1st July 2011

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This 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 Elevation

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

20122010 2011

II III IV I II III

May 2010 – TWG EL Kick-off

Meeting Frankfurt

June 2011 –


Nov 2010 – TWG EL

Meeting Warsaw

March 2011 – TWG EL

Meeting Barcelona

April 2012 –


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Elevation 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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Elevation 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 / others2

• 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 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 Scope


In the scope

Content

• Land elevations:

Absolute gravity-related heights

• Bathymetry

Sea 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

• Coastline

INSPIRE Data Specifications

on Sea Regions, ‘CoastLine’

Feature type

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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 recommended

Heights: EVRS mandated (IR Data Interoperability)

Outside ETRS89 scope

(overseas territories)

MS to decide and identify

Heights: Earth Gravitational Model (EGM Version 2008) recommended

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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 - Structure


INSPIRE Generic

Conceptual Model D2.5

Coverages (Domain and Range)

App. Schema

ISO

Standards

Elevation - Base

App. Schema

Elevation – Vector Elements

App. Schema

Elevation - Coverages

App. Schema

Elevation - TIN

App. Schema

INSPIRE Elevation

Data Product Specification

D2.8.II.1

INSPIRE Directive

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UML Model – Application schemas


Describing2

� 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’

Elevation -Base

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Describing2

� Generic abstract class

� ‘ElevationVectorObject’

� Specialized features types

� Points

‘SpotHeight’, ‘SpotDepth’

� Lines

‘ContourLine’, ‘DepthContour’

� Auxiliary objects

‘BreakLine’, ‘VoidArea’, ‘IsolatedArea'

Elevation –

Vector Elements

Points LinesSpot Height

Spot DepthContour

Line

Depth

Contour

Break Line

Void Area

Isolated

Area Elevation

Vector Object

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Describing2

� 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

Elevation –

Coverages (Grids)

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Describing2

� Main class

� ‘ElevationTIN’

� Elevation property

/ Surface

� ‘height’ / ‘depth’

� ‘DTM’ / ‘DSM’

� Conformity to

� ISO 19107:2003 –

Spatial Schema

Type ‘GM_Tin’

Elevation -TIN

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Open 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


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

Thank you for your attention!!

[email protected]

[email protected]

data specification elevation v2 · 2011-07-13 · data specification elevation v2.0 jordi escriu...

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