1. LUCAS Monitoring the European Union territory using a grid approach Maxime KAYADJANIAN Eurostat F-2

2. LUCAS 100 000 points systematically sampled LUCAS Grid Reason: compromise between budget and required statistical representativity at EU level

3. LUCAS Why a systematic GRID ? LUCAS Grid LUCAS is a multipurpose system for monitoring: Land Use / Land cover Landscape and Environmental features Reason: all the territory has to be covered the same way to ensure equiprobabilty of observations

4. LUCAS 300 m Specifications LUCAS Grid A two-stage sampling GRID 10.000 PSU10 SSU Reason: optimizing trip for visiting points in the field X

5. LUCAS Particular case LUCAS Grid ItalySpain Reason: complying with already existing national system MAST system Distance inter PSU = 20 km (not 18 km) AGRIT system Distance inter SSU = 300 m east-west 500m north-south

6. LUCAS Construction of the GRID

7. LUCAS Construction (1/3) LUCAS Grid Choice of projection system: GRS80 + UTM One sampling plan per country to limit ground distortion

8. LUCAS Construction (2/3) LUCAS Grid Grid generated in the UTM zone of the country Origin chosen pseudo-randomlyTotal coverage of country

9. LUCAS Construction (3/3) LUCAS Grid SSUs selected according to SABE and SCOLE (© Megrin) boundaries Selection of SSUsUncompleted PSUs

10. LUCAS Geometrical quality of the sampling plan LUCAS Grid

11. LUCAS Geometrical quality of the sampling plan LUCAS Grid Are points regularly spread on the ground? N S 18 km N S 18 km ? E W N S 18 km Once grid generated...…in the UTM projection system... …how much ground distance is affected ?

12. LUCAS LUCAS Grid Largest line of PSUs in France...…shows a longitudinal angle reduction apart from central meridian - 45m …it corresponds to a reduction of 45m on the ground 500 km apart from central meridian. Geometrical quality of the sampling plan

13. LUCAS LUCAS Grid How many points are affected by distortion ? Point out of central median zone  30% Geometrical quality of the sampling plan Conclusion: distortions are negligible for statistical estimates

14. LUCAS The case of SPAIN (MAST) No distortion but small gaps LUCAS Grid Geometrical quality of the sampling plan

15. LUCAS Reaching the point on the ground LUCAS Grid A fundamental aspect to ensure a correct monitoring

16. LUCAS Reaching the point on the ground 3 basic tools LUCAS Grid 3/ GPS for navigating along transects 1/ Topographical maps for navigating between PSUs 2/ Aerial photo for reaching precisely the SSU

17. LUCAS Reaching the point on the ground LUCAS Grid Positional accuracy 3 m At the point: observation in a 3 m window

18. LUCAS Reaching the point on the ground LUCAS Grid

19. LUCAS Implementation problem Projection of UTM x,y into national system LUCAS Grid Systematic shift of about 200 m between GPS co-ordinates and location on the photo detected during the ground mission control, in: Luxembourg: specific parameters for datum Greece & Portugal: bug in the GIS soft For these countries the original sampling plan has been corrected in return

20. LUCAS Conclusion Reaching the point: Good quality of field document Location of points: only minor distortion in the sampling plan (no impact on estimates) Well documented LUCAS can be considered as a strong system: