PRODUCTION PROCESSES FOR A HARMONISED E UROPEAN POPULATION GRID Marja Tammilehto-Luode Rina Tammisto Statistics Finland October 2012European Forum for Geostatistics 2012 Conference, Prague 1

Outline A part of guidelines material for NSIs A description of three types of process flows More detailed instructions for –Collection –Reprojection –Creation of grid identifier –Aggregation population data into LAEA grids –Process of grid cell intersection October 2012EFGS 2012 Prague Conference 2

Guidelines for NSIs The guidelines will –be available on EFGS web site early 2013 –focus on a harmonised European population grid compatible with INSPIRE specification –describe various production flows –describe various software approaches following the production work flows –be finalised during the GEOSTAT 1B project including recommendations for metadata and disclosure control and examples of spatial analysis October 2012EFGS 2012 Prague Conference 3

4 1 Collection II Reprojection III Creation grid identifiers IV Aggregation population by LAEA grids V Join with LAEA grid net I Collection II Creation of grid centroids III Reprojection centroids into LAEA IV Create grid identifiers by calculation or by spatial join with the LAEA grid net V Aggregate population sums by LAEA grids V I Join with the LAEA grid net I Collection II Intersection with grid net III Calculating the area of intersections IV Distribution of the population according to the area of intersection V Dissolve based on LAEA grid data identifiers and calculation of population VI Join with the LAEA grid net National micro data in use National grid data in use – grid cell size smaller than 1km Three types of process flows for generating population grids National grid data in use – grid cell size 1 km

Production process: ”Aggregation” To be used –when micro data is available and data maintenance in ETRS/LAEA is possible October 2012EFGS 2012 Prague Conference 5 I Collection II Reprojection III Creation of grid identifiers IV Aggregation population by LAEA grids V Join with LAEA grid net

Production process: ”Recast” To be used: –when national grid data already exists –preferably when national grid data has smaller grid cells than 1km2 due to data quality October 2012EFGS 2012 Prague Conference 6 I Collection II Creation of grid centroids III Reprojection centroids into LAEA IV Create grid identifiers by calculation or by spatial join with LAEA grid net V Aggregation population by LAEA grids VI Join with LAEA grid net

Production process: ”Grid cells intersection” To be used –when national grid data already exists –as an alternative to ”Recast” –when only 1km2 national grids are available (good alternative) October 2012EFGS 2012 Prague Conference 7 I Collection II Intersection with grid net III Calculating The area of intersections IV Distribution of population according to the area of intersection V Dissolve based on LAEA grid data identifiers and calculation of population VI Join with LAEA grid net

Important steps in the production process, 1 Collection Country clip (GRID_ETRS89_LAEA_1K) + National data Analysing the spatial extent of the grid net Coverage of the country clip against national map data / primary data or national grid data Reprojection National micro data or Centroids of grid cells of national grid data ArcGIS or GVSIG October 2012EFGS 2012 Prague Conference 8 Back to ” Aggregation ”

Important steps in the production process, 2 Creation of GRID identifiers Based on grids’s lower left corner coordinates truncated by grid cell size Alternative ways by using SAS or SQL or ArcGIS or GVSIG, Excel Aggregation Population data to LAEA grids Aggregation micro data by SAS or SQL Aggregation grid cell centroids by ArcGIS or GVSIG Join (and aggregation) with the LAEA Grid net by ArcGIS Aggregation data and join with LAEA Grid net in GVSIG October 2012EFGS 2012 Prague Conference 9 Back to ” Aggregation ”

Grid cells intersection The whole workflow by ArcGIS (or other GIS sofware) Intersection of a LAEA projected national grid with the LAEA grid Calculation of the areas of intersections Distribution the population according to the area of intersection Dissolve based on the LAEA grid identifiers Join to LAEA grid October 2012EFGS 2012 Prague Conference 10 Back to ” grid cells intersection ”

Conclusion Guidelines for producing harmonised European population data Instructions include Detailed descriptions about alternative workflows Program statements/SAS, SQL, Excel Visual captures of GIS programs Will be available on EFGS web site early 2013 Supplements by the end of GEOSTAT project October 2012EFGS 2012 Prague Conference 11

Thank you for your attention! 25 October 2012EFGS Conference, Praha