1 Quality Assessment in grid statistics Data quality and coverage ESTP course on Geographic Information Systems (GIS): Use of GIS for making statistics in a production environment Statistics Norway, Oslo, 26th to 30th of March 2012 Attribution (by) Licensees may copy, distribute, display and perform the work and make derivative works based on it only if they give the author or licensor the credits in the manner specified by these. Mr Vilni Verner Holst Bloch MSc Resourcs Geography and Landscape Ecology Statistics Norway 460 Construction and service statistics Oterveien 23 N-2225 Kongsvinger NORWAY Tel: Mob

2 Standard for Quality Reports To be interpreted into GIS terms - geographical accuracy - geographical coverage - georeferencing methods …

3 Population and Housholds unit IT Archive unit Housing and Buildings unit Population and housing example

4 Statistics Dwelling statistics Housing census Constructions Builfing stock Levekårundersøkelser Sources Properties register Population register Dwelling surveys Dwelling sales ingormation Ownership register Census 2001 Actual addresses Elevator register Tax information Water supply maps Sewage maps … Lots of variables, sources and statistics attached to dwellings

5 Principles Use best sources : - use authorative sources first (e.g. …) - use newest information (e.g. new dwelling sales before old…) - imputation if enhancing statistics (coverage, detail level, bias etc…)

6 Persons without dwelling Inhabited dwellings vacant dwellings new dwellings Micro file ID N - 1 (often N – N, sometimes 1 - 0) Published variablesNew variables AB C persons dwellings

7 Percentage unknown Urban/rural1,060,130,080,040,050,11 Building year 9,129,469,219,028,42 Number of rooms 11,4911,2611,6711,6611,54 Utility floor space 7,677,106,595,845,33 Number of baths 11,0610,8511,1911,0510,88 Number of WC 10,9810,7811,1210,9510,79 Number of floors in building 0,500,08 Kitchen 0,880,93 Floor entrance 0,140,16

: Dwellings, by number of floors in the building (M) municipality unknown Kristiansand4757 Oslo656 Surnadal446 Steinkjer348 Drammen193 Bardu128 Tønsberg124 Sandefjord120 Sandnes109 Halden104 municipalityUnknown Oslo336 Åsnes105 Volda100 Grue89 Flora88 Frøya69 Gaular67 Øystre Slidre56 Fauske55 Hitra : Dwellings, by position (floor) in the building (M) Quality in dwelling statistics (municipalities)

9 Water supply points from digital maps Example water supply Dwellings and distance to water supply

10 Dwellings on grids Dwellings per 5x5 km grid cell Oslofjord area Southern Norway mountains

11 Dwellings on grids Region Oslo Region Kongsvinger Dwellings per 5x5 km grid cell

12 Dwellings on grids Dwellings per 250x250m

13 Quality in dwelling statistics on grid 2010 MissingOn gridStatisticsDifference % VarTitle (EN)2010 dwe_todwDwellings in all ,03 dwe_detDwellings in detached houses ,00 dwe_2dwDwellings in tomannsboliger ,38 dwe_rowDwellings in rekkehus, kjedehus og andre småhus ,10 dwe_multDwellings in boligblokk ,82 dwe_comDwellings in bofellesskap ,14 dwe_othDwellings in andre bygningstyper ,87 dwe_aveaAverage utility floor space Missing or incorrect coordinates. Norway.

14 Dwellings with no information on utility floor space Dwellings in all Quality in dwelling statistics on grid Coverage for utility floor space. Whole country: 92,9 % 1x1 km grid cells in Trondheim area 60% 85%

Change (N buildings)N (5x5 km) , , og mer3632,9 No change ,1 Decrease ,7 No buildings8 264

16 Buildings. Shares per 5x5 km 2 and year Inspection of changes. Changes in coordinates due to wash of registers or real changes?

17 Buildings. Change 2007 – x5 km 2 Net more buildings Net fewer buildings Net more (red) and fewer (blue) buildings

18 Buildings. Change 2007 – x5 km 2 Real changes or due to different administrative routines?