1 quality assessment in grid statistics data quality and coverage estp course on geographic...

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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 environmentStatistics Norway, Oslo, 26th to 30th of March 2012

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Mr Vilni Verner Holst BlochMSc Resourcs Geography and Landscape EcologyStatistics Norway460 Construction and service statisticsOterveien 23 N-2225 Kongsvinger NORWAYvvh@ssb.noTel: +47 6288 5097Mob. +47 9482 2532

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Standard for Quality Reports

• To be interpreted into GIS terms- geographical accuracy- geographical coverage- georeferencing methods…

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Population and Housholds

unit

IT Archive unit

Housing andBuildings

unit

Population and housing example

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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

• …

Lot’s of variables, sources and statistics attached to dwellings

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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…)

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Persons ”without dwelling

Inhabited dwellings

”vacant” dwellings

”new” dwellings

Micro file

ID

ID

N - 1 (often N – N, sometimes 1 - 0)

Published variables New variables

A B

C

persons

dwellings

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Percentage unknown

2006 2007 2008 2009 2010 2011

Urban/rural 1,06 0,13 0,08 0,04 0,05 0,11

Building year   9,12 9,46 9,21 9,02 8,42

Number of rooms   11,49 11,26 11,67 11,66 11,54

Utility floor space   7,67 7,10 6,59 5,84 5,33

Number of baths   11,06 10,85 11,19 11,05 10,88

Number of WC   10,98 10,78 11,12 10,95 10,79

Number of floors in building   0,50 0,08

Kitchen   0,88 0,93

Floor entrance   0,14 0,16

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08455: Dwellings, by number of floors in the building (M)

municipality   unknown ↓

Kristiansand 4757

Oslo 656

Surnadal 446

Steinkjer 348

Drammen 193

Bardu 128

Tønsberg 124

Sandefjord 120

Sandnes 109

Halden 104

municipality Unknown ↓

Oslo 336

Åsnes 105

Volda 100

Grue 89

Flora 88

Frøya 69

Gaular 67

Øystre Slidre 56

Fauske 55

Hitra 53

08457: Dwellings, by position (floor) in the building (M)

Quality in dwelling statistics (municipalities)

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Water supply points from digital maps

Example water supply

Dwellings and distance to water supply

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Dwellings on gridsDwellings per 5x5 km grid cell

http://www.ssb.no/emner/01/01/20/tettstedkart/main.html

Oslofjord area Southern Norway mountains

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Dwellings on grids

http://www.ssb.no/emner/01/01/20/tettstedkart/main.html

Region Oslo Region Kongsvinger

Dwellings per 5x5 km grid cell

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Dwellings on gridsDwellings per 250x250m

http://www.ssb.no/emner/01/01/20/tettstedkart/main.html

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Quality in dwelling statistics on grid

2010

Missing On grid Statistics Difference %

Var Title (EN) 2010 2010 2010 2010

dwe_todw Dwellings in all 23 923 2 300 002 2 323 925 1,03

dwe_det Dwellings in detached houses 12 183 1 207 720 1 219 903 1,00

dwe_2dw Dwellings in tomannsboliger 2 911 208 685 211 596 1,38

dwe_row Dwellings in rekkehus, kjedehus og andre småhus 2 944 264 877 267 821 1,10

dwe_mult Dwellings in boligblokk 4 282 518 710 522 992 0,82

dwe_com Dwellings in bofellesskap 471 40 724 41 195 1,14

dwe_oth Dwellings in andre bygningstyper 1 132 59 286 60 418 1,87

dwe_avea Average utility floor space 109 123    

Missing or incorrect coordinates. Norway.

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Dwellings with no information on utility floor space

Dwellings in all

Quality in dwelling statistics on gridCoverage for utility floor space. Whole country: 92,9 %

1x1 km grid cells in Trondheim area

60%

85%

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2008 - 2012      

Change (N buildings) N (5x5 km)    

+ 1 - 9 4 279 34,3

+ 10 - 99 2 496 20,0

+ 100 og mer 363 2,9

No change 3 638 29,1

Decrease 1 707 12 483 13,7

No buildings 8 264    

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Buildings. Shares per 5x5 km2 and year. 2007-2012.

Inspection of changes. Changes in coordinates due to ”wash” of registers or real changes?

17Buildings. Change 2007 – 2012. 5x5 km2

Net more buildings

Net fewer buildings

Net more (red) and fewer (blue) buildings

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Buildings. Change 2007 – 2012. 5x5 km2

Real changes or due to different administrative routines?