1. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz1/X Ing. Jaroslav Kraus, Ph.D. Mgr. Štěpán Moravec DISAGGREGATION METHODS FOR GEOREFERENCING INHABITANTS WITH UNKNOWN PLACE OF RESIDENCE : THE CASE STUDY OF POPULATION CENSUS 2011 IN THE CZECH REPUBLIC 24th October, EFGS 2013 Conference, Sofia

2. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz2/X STARTING SITUATION  Total number of usually resident population: 10 436 560  Georeferenced inhabited building points stored in the Register of Census Districts and Buildings managed by CZSO: 1 790 122  Georeferenced population with exact place of usual residence (x,y coordinates): 10 343 479  High coverage of georeferenced data (above 99 %):  93 thousands inhabitants not linked to the exact place of their usual residence (0,9 % of the total census population) 10 436 560 – 10 343 479 = 93 081 But, the census data of these inhabitants are linked to the level of statistical districts

3. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz3/X Cause: missing, incomplete or incorrect address data Structure of the people with unknown place of residence:  homeless people  people living in emergency buildings or shelters  people living in buildings without final approval Possible solution for distribution of these people into buildings with x,y coordinates or into grids:  Application of some disaggregation method  Testing of 3 disaggregation methods via ArcGIS software DESCRIPTION OF THE PROBLEM

4. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz4/X Case study: small town Abertamy in the northern part of the CR  Total number of census population: 1 213  Number of not georeferenced inhabitants: 46  Total number of statistical districts: 6  Number of affected statistical districts: 6  Number of inhabited buildings: 214 CASE STUDY

5. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz5/X 1. Layer of statistical districts with number of not georeferenced inhabitants 2. Layer of population grids with number of georeferenced inhabitants

6. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz6/X METHOD 1: CREATING NEW RANDOM BUILDING POINTS  Creates a specified number of random point features. Random points can be generated in an extent window, inside polygon features, on point features, or along line features  Parameters: –Number of Points –Minimum Allowed Distance –Others

7. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz7/X METHOD 1: CREATING NEW RANDOM BUILDING POINTS

8. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz8/X METHOD 1: RECALCULATION OF POPULATION BY RANDOM BUILDING POINTS (1) Source: Using field calculator: Create Random Values, Iowa State University

9. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz9/X 1.Creating new random building points 2.Defining population (from random interval) for new random building points 3.Recalculation of limit number of inhabitants (e.g. defined by information from statistical district )  Source: ArcGIS10 Help METHOD 1: METHODOLOGY

10. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz10/X ArcGIS 10: method Median Center (or Mean Center, Central Feature) METHOD 2: CREATING OF POPULATION CENTERS OF GRAVITY (1)

11. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz11/X MEAN CENTER (SPATIAL STATISTICS)  Identifies the location that minimizes overall Euclidean distance to the features in a dataset  Mean Center (and Median Center) are measures of central tendency  For line and polygon features, feature centroids are used in distance computations  The Case Field is used to group features for separate median center computations (e.g. by statistical districts)  Source: ArcGIS10 Help

12. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz12/X METHOD 2: METHODOLOGY (1) 1.Calculating Central Value (Mean Center, Median Center) → Layer of spatially weighted population centers of gravity

13. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz13/X 2.Spatial join for linking persons with unknown place of residence into weighted center of gravity METHOD 2: METHODOLOGY (2)

14. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz14/X Aim:  To distribute not georeferenced population just into grids, not into particular buildings (x,y coordinates)  To respect known spatial distribution of population (based on georeferenced population only) Methodology: 1.To calculate a population weight of each inhabited grid segment within affected statistical district Population weight of grid segment i = METHOD 3: CALCULATION OF POPULATION WEIGHTS OF GRIDS Population number of grid segment i Total population of statistical district j

15. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz15/X 1. Layer of population grids with number of georeferenced inhabitants 2. Layer of population grids with relative population weight

16. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz16/X 2.To calculate a population number distributed to each inhabited grid segment within affected statistical district Population weight of grid segment i * Total number of not georeferenced persons within statistical district j 3.Rounding of the population number distributed to each inhabited grid segment to an integer value 4. Add the number of distributed not georeferenced persons to the initial number of georeferenced inhabitants for each grid segment METHOD 3: METHODOLOGY

17. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz17/X 2. Layer of population grids with relative population weight 3. Layer of population grids with number of additionally distributed persons

18. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz18/X  Different types of irregularities and deviations:  Problem with rounding (increase or decrease of the distributed population number)  Problem with statistical districts without inhabited buildings  Problem with grids with the same population weight Definition of additional assumptions and consequent manual corrections required METHOD 3: METHODOLOGICAL ISSUES

19. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz19/X CONCLUSION Pluses and minuses of method 1 and 2: inhabitants distributed to the level of buildings distribution according to spatial distribution of inhabited buildings Pluses and minuses of method 3: distribution according to spatial distribution of population inhabitants distributed to the level of grids  All mentioned methods are used for recalculation of people with unknown exact place of residence  There is relatively enough „handworks“ to do it → some automatizations of processes are important  Finally, recalculation on single (personal) records are aim of the whole process

20. CZECH STATISTICAL OFFICE | Na padesátém 81, 100 82 Prague 10 | czso.cz20/X Thank you for your attention.