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Developing a Census Geography Programme

Developing a Census Geography Programme. Overview. Background : Recommendations on Census Geography Building a Census Geography Programme : Definition of National Geography Constructing an EA-level Database Institutional/Organizational aspects Participation in the NSDI

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Developing a Census Geography Programme

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  1. Developing a Census Geography Programme 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  2. Overview • Background: • Recommendations on Census Geography • Building a Census Geography Programme: • Definition of National Geography • Constructing an EA-level Database • Institutional/Organizational aspects • Participation in the NSDI • Challenges/Conclusion 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  3. Census Geography Programme: A Continuous Process • The recommendations derived from our EGM and Workshops on GIS and census mapping emphasized the need for countries to consider the census geography programme as a continuous process, rather than the sequential mapping and dissemination operations. • It was also emphasized that the use of and application of contemporary geospatial technologies and geographical databases is beneficial at all stages of population and housing census process. Geospatial improve the efficiency in the preparatory, enumeration, processing and dissemination phases of the census 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  4. Census Process: Maps support Pre-Census (Pre-enumeration: maps ensure consistency, prepare) Census (Enumeration: maps support data collection, monitor) Post-Census (Post-enumeration: analyze, display and disseminate) 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  5. Geospatial Technologies at all stages (Pre-enumeration) (Enumeration) (Post-enumeration) Digital Mapping Digital Mapping Statistical Database Census Database Databases Maintenance GIS GIS Aerial Photo. GIS Satellite Imagery GPS/PDA Internet Mapping GPS EAs Units Administrative and Reporting Units 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  6. Integrating geospatial technologies: Main approaches • Various combinations: • Since we have to integrate different geospatial tools at different stages • Three main approaches: • Post-census Approach • Full Census Program • Mixed Approach • Choice of the approach: should be based on the needs and available resources 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  7. National Census Geography • Consists of an administrative hierarchy: • Every country has its own specific administrative hierarchy • A system by which the country and each lower level set of administrative units (except the lowest) are subdivided to form the next lower level. • Hierarchy made up ofadministrative areas: • Administrative areas for which census data will be reported • Normally includes statistical reporting units 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  8. Illustration of a nested admin.Hierarchy • Relationships among all types of administrative and reporting unit boundaries are defined. • hierarchical levels may have actual administrative roles • Other units may have statistical roles alone 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  9. Enumeration Area (EA) • EAs are the operational geographic units for the collection of census data • Some facilitate census data collection while others pertain to the usefulness of EAs in producing output products • i.e., the relationship between data collection and tabulation units. • Delineation of EAs is similar whether manual or digital cartographic techniques are used 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  10. Coding Scheme • A unique numeric code needs to be assigned to each enumeration area or administrative unit. • This is the numeric code that provides the link between the aggregated census data and the digital EA boundary database stored in a GIS. • Ideally the coding scheme needs to be determined on a country by country basis. • The most important principles when designing a coding scheme are: flexibility, expandability, intuitiveness and compatibility with other coding schemes in use in the country. 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  11. Example of a generic EA coding scheme • Geographic units are numbered at each level of the administrative hierarchy—usually leaving gaps between the numbers to allow for future insertion of newly created zones at that level. 1 2 0 3 2 4 4 0 1 2 0 0 5 province district Enumerationarea locality 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  12. Geocoding Concept • Geocoding represents the connection between statistical observations and real-world locations expressed in terms of latitude and longitude or other locational attributes • Geocoding is a way to ensure the data know where they are! • Geo-coding concept: not limited to address-matching • Geocoding covers a continuum of spatial scales: from individual housing units to enumeration are level up to higher administrative or national levels. 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  13. Definition of national geography: summary • Administrative areas for which census data will be reported: One of the earliest decisions in Census planning • A census geographic hierarchy • A coding scheme: flexible and expandible • Geocoding: link between geographic features and census data attributes 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  14. Constructing an EA-level Databasefor the Census: development stages • Geographic data sources for EA delineation • Inventory of existing data sources/Additional geographic data collection • Data conversion • Digitizing/Scanning + Ratser-to-Vector conversion • Editing Geographic features • Constructing and maintaining topology for geographic features • Data integration • Georeferencing/Coding • Combining and integrating/Additional delineation of EA boundaries • Parallel activity • Develop geographic attribute database/Metadata 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  15. Institutional/Organizational Issues • A specialized in-house Cartography/GIS unit • Building technical and human capacities: • Training-GIS skills • Retaining-incentives • National Spatial Data Infrastructure (NSDI) 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  16. National Spatial Data Infrastructure (NSDI) • Spatial Data Infrastructure Concept: • Important as physical infrastructure assets such as roads, communications networks, and other public utilities • Definition: • The technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatialdata • Institutionel cooperation: • Common Geographic Reference • Data sharing/ Interoperability • Satnadards/Metadat 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  17. Reference Data: some core layers • Geoditic network • Administrative Boundaries • Population centres / gridded Population density • Hydrography • Elevation • Roads and Railroads • Cadastral • Geographical Names 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  18. Spatial Data Infrastructure (SDI) • National • Part of a nation’s e-Gov strategy • Regional: • Africa: AFREF/AFRICOVER • Americas: SIRGAS • Asia and the Pacific: APSDI • Europe: INSPIRE/ESDIN • Global: • GSDI Assiociation: www.GSDI.org • Global Mapping • UNGIWG-UNSDI (SALB) 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  19. Some good news: WG on Census Cartography • A new Working Group on Census Cartography within ICA • TOR: • http://cartography.tuwien.ac.at/ica/index.php/Commissions/Working-groups • Census Cartography WG website (click on the Terms of Reference tab): http://cartography.tuwien.ac.at/ica/workinggroups/census/ • News: • The December 2008 ICA Newsletter (No. 51) is available on the ICA website at: http://cartography.tuwien.ac.at/ica/index.php/Newsletter/Newsletter . There is an article on the Census Cartography WG on page 14. • ICA-2009 Chile: special sessions on census cartography 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  20. Challenges/Conclusion National Statistical Organizations should: Develop GIS as a long term project: To prepare the census enough in advance Too expensive for the census only To be used beyond the census as infrastructure for other statistical purposes (other sources, sample frame...) Ensure the availability of adequate resources to that end; Actively participate, in partnership with other national authorities, in the development of a national geographical information capacity, including the National Spatial Data Infrastructure (SDI). 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  21. THANK YOU! 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  22. Implementing a GIS • Consider the strategic purpose • Plan for the planning • Determine technology requirements • Determine the end products • Define the system scope • Create a data design • Choose a data model • Determine system requirements • Analyze benefits and costs • Make an implementation plan Source: Thinking About GIS, Third EditionGeographic Information System Planning for Managers 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  23. Example of Administrative Hierarchy • for the purposes of the census a country may have been divided into seven hierarchical levels in urban areas and six in rural areas Generic census geographic hierarchy 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  24. Coding scheme (cont.) • In cases where administrative and reporting units are not hierarchical, special coding conventions need to be developed. • Important to be completely consistent in defining and using the administrative unit identifiers, since they are the link between the GIS boundaries and the tabular census data. • The census office should therefore maintain a master list of EA and administrative units and their respective codes and commit any changes made to the master list to the GIS and census databases. 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  25. Main NSDI Components 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

  26. Coding Scheme (cont.) • However, the rules used to assign codes need to be unambiguous and should be designed in collaboration within the NSO, especially between the mapping/GIS unit and those managing the data core. • The most important principles when designing a coding scheme are • flexibility, • expandability, • intuitiveness and • compatibility with other coding schemes in use in the country. 4th Africa Symposium on Statistical Development: “Processing Census Data in the Africa 2010 Round of Population and Housing Censuses” Luanda, Angola 09-13 February 2009

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