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A Spatial Reference System (by co-ordinates) for Europe

A Spatial Reference System (by co-ordinates) for Europe. Claude.Luzet@megrin.org. topics. Reference systems : a reminder Transformation and conversion Spatial Reference System Workshop : a 1999 SAI/MEGRIN initiative Spatial Reference System for Europe : recommendations.

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A Spatial Reference System (by co-ordinates) for Europe

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  1. ASpatial Reference System(by co-ordinates)for Europe Claude.Luzet@megrin.org

  2. topics • Reference systems : a reminder • Transformation and conversion • Spatial Reference System Workshop : a 1999 SAI/MEGRIN initiative • Spatial Reference System for Europe : recommendations

  3. ? egg or grapefruit ? do we live on the same planet?? ….why different spatial reference systems?

  4. geo-referencing by co-ordinates

  5. geodetic datum Z Y X

  6. map coordinates N E

  7. ellipsoïd to plan N h  E 

  8. heights earth surface geoid h H ellipsoid N

  9. N, E, (h) N, E, (h) ,  (h) ,  (h) X, Y, Z X, Y, Z change of system Datum 1 Datum 2 conversion conversion transformation

  10. why different systems (1)? earth surface geoid ellipsoid

  11. why different systems (2)?

  12. issues • Conversion • mathematical • exact (exception : N) • Transformation • empirical • precision depending on measurements • All changes • time-consuming • risks of errors, discrepancies

  13. problems... • Limitless and ever expanding list of ’systems’ (national, regional, local) • Increasing needs for large amount of data to be processed ‘on-the-fly’ • What specification to include in the CEC call for tenders ? • Etc ...

  14. … and solutions • SAI / MEGRIN Expert Workshop • Marne la Vallée, 29-30/11/99 • 15 participants • CEC (JRC, DG13, EUROSTAT) • EEA, EUROCONTROL, MEGRIN, EUROGI • Geodesy Experts : EUREF, ISO, CEN, OGC, CERCO, etc..

  15. 1- the European system already exists for the experts • ITRS : the global reference • European Continental Plate moves uniformly ~3cm per year

  16. 1- the European system already exists for the experts • ITRS : the global reference • European Continental Plate moves uniformly ~3cm per year • The EUREF sub-Commission of IAG • ETRS89 • stable • shift to global ITRS known (and WGS84) • transfo. parameters known for most European countries!

  17. 2- recommendations • No map projection suitable for all pan-European applications • Geo-referenced co-ordinates for the CEC would be geographic co-ordinates () on ETRS89 • NMAs to place 1~2 m. accuracy transformation algorithms in public domain • EUREF/CERCO to collect and manage high accuracy transformations

  18. 3- heights • nationally defined heights may differ by several dm. (2.3 m. for Belgium)

  19. 3- heights • nationally defined heights may differ by several dm. (2.3 m. for Belgium) • no uniform European height system available yet • EULN in preparation by EUREF/EUVN • Recommendation : that the CEC adopts the EUVN results when made available

  20. Conclusions • interoperability and integration of data from different sources still a key issue • co-ordinate interoperability is an easily overcome obstacle: • recommend implementation of the existing common reference systems (ETRS89, EULN) • distribute ‘validated’ transformation tools

  21. proceedings edited by JRC/SAI also available at http://www.megrin.org merci

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