1. Institute for Environment and Sustainability
European Grid workshop: Presentation of results Proposal for a European Grid System
Alessandro Annoni
European Commission
Joint Research Centre
Institute for Environment and Sustainability
General LMU profile:
Deals with spatial information
Move from sectorial support to horizontal support
Full cycle from applied research to pre-operational testing
Geographical coverage: EU 25
Competencies:
Geo – Information services
Earth observation
Integrated spatial analysis
Thematic foci:
Forestry
Natural hazards
Agri-environment
Landscape analysis
Urban development

2. Background
Workshop on European Reference Grids organized by the JRC (Ispra, October 2003) following requests of
EC services and the EEA
INSPIRE IMS wg recommending that “a Europe-wide reference grid be devised and adopted in order to facilitate the management and analyses of spatial information for a variety of applications”.
interest of NSIs expressed in previous occasions (Eurostat meeting, Luxembourg,1999).

3. ….the preparation..
Close collaboration with NMAs through EuroGeographics
Spatial reference system ws
Map projection system ws
2nd EuroSpecs ws
European Vertical Reference System ws…
Need to involve NSIs
Need to involve leading Grid initiatives (users & producers)
Need to involve Commission Services and European stakeholders (EEA, ETCs, …)
Need to involve GIS industry

4. Participants European Commission National Statistical Institutes
JRC, Eurostat, DG Regio
National Statistical Institutes
Statistics Denmark, Finland, Sweden
National Mapping Agencies
IGN Spain, OS GB, Ger0an Federal Agency for Cartography and Geodesy, Norwegian NMA, OS Northern Irelandm Cyprus Department of Lands and Surveys, Instituto Geografico Portugues
European Organizations and Agencies
EEA, ETC/Nature Protection and Biodiversity
Users and Experts
Botanical Museum, Finnish Museum of Natural History, UMS 2414 RIATE, Institute of Botany, University of Vienna, Bundesamt für Bauwesen und Raumordnung (ESPON), EUREF, Vilnius Gediminas Technical University, Department of Geodesy
GIS Software Industry
INTERGRAPH, Autodesk Europe

5. Structure thematic sessions and working groups
in depth overview and comparative analysis of existing EU/International initiatives, projects and regulations making use of geographical grids
(e.g. ICP-Forest, LUCAS, ESPON, EEA Atlas, Atlas Florae Europaeae, EUSIS, MARS-CGMS,..)
evaluation of current and previous experiences to build national & trans- national grids
(e.g. TANDEM, Nordvic, )

6. Why a grid ? as a framework for collection of « alternative » data,
to aggregate « confidential / privacy » data,
for analysis of raster-based statistical indicators,
to convert different data structure to a common denominator, ...

7. examples of Grid parameters used in different initiatives

8. Questions addressed
The workshop participants were asked to answer specific questions like:
Is a unique EU grid possible (long term vision)?
How can convergence in the future be achieved?
How to increase the integration between existing grids?
Which spatial-statistical methods are available and recommended?
What about Standardisation and Certification of proposed solution(s)?

9. Definition of Grid
“A grid for representing thematic information is a system of regular and geo-referenced cells, with a specified shape and size, and an associated property”.

10. The recommendations in short
To reaffirm the recommendations of the Spatial Reference Systems ws:
To adopt ETRS89 as geodetic datum and to express and store positions, as far as possible, in ellipsoidal coordinates, with the underlying GRS80 ellipsoid [ETRS89] ….
To reaffirm the recommendations of the Map Projection Systems ws:
To adopt ETRS89 Lambert Azimuthal Equal Area coordinate reference system [ETRS-LAEA], for statistical analysis and display.
To adopt ETRS89 Lambert Conic Conformal [ETRS-LCC] for conformal pan-European mapping at scales smaller or equal to 1:500,000.
To adopt ETRS89 Transverse Mercator [ETRS-TMzn], for conformal pan-European mapping at scales larger than 1:500,000….
To continue to promote the wider use of these standards within all member states and internationally, by appropriate means (recommendations, official statement, …).

11. The recommendations in short
To adopt a common European Grid Reference System for Reporting and Statistical Analysis.
The system should be able to store regular grids and should be designed as reference for future Grids related to European territory:
easy to manipulate
hierarchical
based on a common European Grid Coding System
based on units of equal area
adopting ETRS-LAEA and having a clear and simple relation to it
able to manage time stamps
following the quality principles described in ISO
the Grid Data Model should be fully and publicly documented
transfer of Grid data must be based on non proprietary open formats
Metadata must be produced and updated to describe specific Grid characteristics and information related to a specific grid unit.

12. The recommendations in short
For converting to and from existing grid structures, it is highly recommended to generate data from the original detailed information.
It is recommended to test for a period of one year with the aim:
to demonstrate benefits of the proposed solution,
to identify and develop tools,
to establish technical guidelines
to develop best practice examples to support the convergence of existing grid data to the common EU grid.

13. The recommendations in short
To encourage future European projects to make use of the standard European grid.
To help in ensuring the future on-line interoperability of existing Grid systems at European and National level by providing examples of best practices and technical guidelines
To continue the process of educating the users of GI in the complex issues associated with coordinate reference systems, map projections, grids, transformations and conversions, …

14. Proposal for a European Grid Coding System
Proposal drafted during the ws
Further elaborated by a panel of experts
Basic assumptions and definitions
Coordinate Reference System
The geographical location of the grid points are based on the Lambert Azimuthal Equal Area coordinate reference system (ETRS-LAEA)
The cartographic projection is centred on the point N 52°, E 10°.
The coordinate system is metric.

15. European Grid Coding System
The grid is defined as hierarchical grid in metric coordinates in power of 10. The hierarchical structure is determining the structure of the grid coding system.

16. European Grid Coding System
Two models evaluated
Direct Coordinate Coding System
Resolution based Coordinate Coding System
Quad-tree Subdivision considered
Explicit indication of resolution level using powers of 10 and 2 SELECTED

17. European Grid Coding System PROPOSED
An explicit indication of hierarchical level is an asset,
all systems previously considered hide the notion of primary and secondary level and require some effort to remember the correspondence between level and precision.
The system proposed seems to overcome most of the problems identified in previous proposals::
The system is based on a primary grid and in two additional sub-levels (secondary and tertiary grid)
The coordinate values are expressed in decimetres.
The primary grid (metric) will have 7 primary levels (first column in Table 1)
Two additional sub-levels are authorised as quadtree subdivision of the primary grid (second column in Table 1) except as for level one, where only on sublevel is authorised to not have sub-decimetre resolution.

18. Quad-tree subdivision

19. Primary level (power of 10) and quad-tree levels (power of 2) for explicit indication

20. Two ways to express the code are proposed:
A fixed length code (here a point is used as a delimiter, which increases readability but is not necessary for automatic processing): Code = Level.QuadtreeLevel.EastCoordinate.NorthCoordinate
A floating length code (again a point as delimiter) which makes the quad-tree level code (the last part) optional, i.e. it has only to be indicated if a quad-tree level is used: Code = EastCoordinate.NorthCoordinate.Level[.QuadtreeLevel]
[.0]

21. Two applications for the explicit indication coding for the example coordinates (578035, 436102)

22. Proposal to COGI Both coding systems: The fixed length code shows
can be easily derived from the coordinate values.
are easily understandable.
The fixed length code shows
more redundancy and less flexibility
i.e. for a change of precision
but the coding rules are straightforward and thus seem to be easier to handle by computers.

23. COGI follow-up Proposal discussed at the last COGI meeting
Need to test the proposed coding system
The coding system could be proposed in future as draft INSPIRE specification (Annex I data theme)
The system is based on ETRS-LAEA already adopted by COGI (also to be proposed as draft INSPIRE specification)
Further work needed, in order to define:
Guidelines for grid data collection and reporting
Guidelines for data transformation to/from grid
Metadata standard for Grid documentation
What about future migration of existing systems?
Short term vs long term strategy
Need of internal consultation in the EC

24. Conclusions Internal consultation Preliminary conclusions
opinion on the recommended systems,
additional information on projects using geographic grids
feedback on encountered problems in case of projects already using the proposed system.
Preliminary conclusions
mandatory use limited to “statistical analysis and display”
standardised tools need to be developed and made available to cope with the required transformations
the hierarchical grid coding system seems appropriate
no request for different cell sizes
the European Grid System is perceived as an important facilitator for data exchange
flexibility is needed to preserve historical archives