United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Use of GIS, Spatial Analysis and Web-based Mapping United Nations Statistics Division United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Outline UN Recommendations/Census Geography Programme Why we use geospatial tools in censuses Building a EA Geographic Database Spatial Analysis Web-based Mapping Services and Applications Handbook on Geospatial Infrastructure in Support of Census Activities United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 UN Recommendations UN Principles and Recommendations for Population and Housing Censuses, Rev.2, recommended the use of Geospatial technologies for improving traditional methods of census mapping (adopted by UNSC in 2007). Other recommendations derived from UN EGM on GIS and Census Mapping emphasized: the need for countries to consider the census geography programme as a continuous process the use of geospatial technologies and information is beneficial at all stages of population and housing census process (GI improves the efficiency in the preparatory, enumeration, processing and dissemination phases of the census) United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Statistical Commission Decision on the Integration of Statistical and Geospatial Information Decision 41/110 (of the SC at its 41 st session in 2010): (b) Recognized the importance of the integration of geographic and statistical information and the opportunities provided in that context by the swift development of information technology, noting that national statistical offices are playing an increasing role in such integration, especially in the area of census management; (c ) Called upon all national statistical offices to actively participate, in partnership with relevant national authorities, in the further development of national geographic information capacity in the context of spatial data infrastructures, taking full advantage of information technology and focusing special attention on the area of improving statistical and geographic metadata compatibility; United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Census Cycle United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 GIS with Census mapping at all stages EAs UnitsAdministrative and Reporting Units GPS Photo/Video GIS Digital Mapping Satellite Imagery Pre-census Census Post-Census GPS/PDA GIS Digital Mapping GIS Internet ( Map-Server ) (Pre-enumeration)(Enumeration)(Post-enumeration) United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Administrative hierarchy Every country has its own specific administrative hierarchy Definition: 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. Administrative areas for which census data will be reported United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 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 United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Coding Scheme EA: a basic geographic feature Need for an identifier: linking the geographic feature to the census data (attributes) recorded for them EAs and administrative units: coding scheme A unique code assigned to each EA, used in data processing Coding scheme: scalability, flexibility, intuitiveness, compatibility Example of a hierarchical coding scheme province districtlocality Enumeration area United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Geocode Any alphanumeric or numeric-only value that will uniquely identify one and only one geographical entity within the set of all similar entities Examples: Mailing address First and second level administrative areas with their name or number Census statistical area numbers Health district number Watershed ID Etc. Geo-coding: not limited to address-matching (commercial use) Source: US Census Bureau United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Why is GIS unique? Can combine spatial and non-spatial data from different datasets in a spatial analysis operation in order to answer questions such as: What is there Identification Where is Location What has changed since Trends What relationships exist between Patterns What is the best route between Optimal path What if Model Source: US Census Bureau United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 A GIS Works on Geocoded Data GIS Maps, tables, reports Statistical Data Geographical Data Geocodes United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Complete EA map with all components overlaid on one map display Main components are: Street network, Buildings EA boundaries layer Annotation, Symbols, Labels Building numbers Neatlines Legend United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Components of a Hypothetical urban EA map United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Entity-Relationship Example: EA entity can be linked to the entity crew leader area. The table for this entity could have attributes such as the name of the crew leader, the regional office responsible, contact information, and the crew leader code (CL code) as primary code, which is also present in the EA entity. Crew leader area CL-code Name RO responsible 1-N EA EA-code Area Pop. 1-1 R United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Implementation of an EA database : Example of an entity table enumeration area United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Components of a digital geographic census database United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial Analysis Geographical features (Conceptual Model) Components selection Attributes Structure Spatial Relationships (explicit -Topolgy) Spatial Analysis United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial relationships Logical connections between spatial objects represented by points, lines and polygons: - point-in-polygon - line-line - polygon-polygon Spatial relationships: - adjacent to; - connected to - near to; - intersects with - within; - overlaps - etc. United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial Analysis Techniques Techniques include: queries, distance measurements, buffering, linear interpolation, point pattern analysis, and cartograms, etc. the main use of spatial analysis is for census products and services United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial Query select features by their attributes: find all districts with literacy rates < 60% select features by geographic relationships find all family planning clinics within this district combined attributes/geographic queries find all villages within 10km of a health facility that have high child mortality Query operations are based on the SQL (Structured Query Language) concept United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Examples: What is at? Features that meet a set of criteria United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Identification of a set of areas United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 is nearest to Point/point Which family planning clinic is closest to the village? Point/line Which road is nearest to the village Same with other combinations of spatial features United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Travelling the Distance: A GPS-based Study of the Access to Birth Registration Services in Latin America and the Caribbean Inter-American Development, March 2012 Using GPS-collected data, the study examines how the distance from households to civil registries affects the probability of birth registration of children aged 0 to 4 (Countries: Bolivia, Dominican Republic and Peru) Confirmation: Distance and location are crucial determinants of many households decisions: Example of results: increasing the distance to the nearest registry office by 25 km is associated with a 4 percentage point increase in the probability of not registering a childs birth in Bolivia, and 12 percentage points in the Dominican Republic. Link:m= m= United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 is near to: Buffer Operations Point buffer Affected area around a Hospital Catchement area of a water source United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Buffer Operations Line buffer How many people live near the polluted river? What is the area impacted by highway noise? United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial Analysis Techniques point-in-polygon analysis Determines whether a point lies inside or outside a polygon. Can be used to compare geo-coded village centroids lying inside and outside hazardous areas such as tropical storm tracks or earthquake zones. Polygon overlay analysis Involves comparison between the locations of two different polygonal data layers. For example, the boundaries of two administrative districts could be compared to troubleshoot errors in the field enumeration process United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 is within: point in polygon Which of the cholera cases are within the containment area United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Problem: We may have a set of point coordinates representing clusters from a demographic survey and we would like to combine the survey information with data from the census that is available by enumeration areas. Solution: Point-in-Polygon operation will identify for each point the EA area into which it falls and will attach the census data to the attribute record of that survey point. United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial aggregation Example of Spatial aggregation: fusion of many provinces constituting an economic region United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial data transformation: interpolation Example: Based on a set of station precipitation surface estimates, we can create a raster surface that shows rainfall in the entire region United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Example of linear interpolation creating contours United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Areas of influence Commuting distances: daily commuters flow United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Modelling: smoothing Evolution of the population beetwen two censuses United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Spatial Analysis Techniques: Cartograms sometimes used to display census results The areas of the original polygons are expanded or contracted based on their attribute values such as population size or voting habits United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Location-allocation problems Site selection Optimal allocation Multicriteria Analysis United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Different Geographies A geography for data collection: EA level or even dwelling level Another geography for data dissemination: Aggregated level (confidentiality) United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Uses of Graphs: Enriching the Understanding of GIS Data Sets Exploratory Spatial Data Analysis Linked Maps, Graphs & Tables Dynamic Feature Selection Animation Visualization over Time United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 GIS capabilities: Visualization United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Web Mapping Architecture (Ref. B. Dickinson) Mapping applications are accessed through standard web technologies to meet the needs of a specific business process or user. Web Services Clients Data Stores KML/ SOAP KML/ SOAP United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Web Map Services A Web Map Service (WMS) is a standard protocol for serving georeferenced map images over the Internet that are generated by a map server using data from a GIS database. (developed by OGC) georeferencedGIS WMS is a widely supported format for maps and GIS data accessed via the Internet and loaded into client side GIS software Most GIS software support WMS GIS APIs United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Cont Client technology: from dumb mapping to smart mapping application - The overall trend for web-based mapping is with more highly interactive, user-driven client interfaces as well as the desire by the general internet user to see the underlying data as a 3D environment and not a 2D flat-earth map. Server-technology: service-oriented architecture (SOA) and broad spatial capabilities United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, Dissemination: web service application United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Digital Data Dissemination Strategy The wide range of potential users of disaggregated census data means that the NSO needs to pursue a multi-leveled digital data dissemination strategy. Broadly, we can distinguish between the following types of users: Advanced GIS users Computer literate users Novice users United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Handbook on Geospatial Infrastructure in Support of Census Activities- Available in the six UN official languages - Cook-book to illustrate the role of geospatial technology in each step of the census process - Audiences: managerial and technical - Each country has to find its own best possible solution United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Conclusions Geographic Database/Topology Variety of techniques: buffering, overlay, modelling: Although spatial analysis is sometimes used during the enumeration phase (clustering, for example, can aid in identifying housing units to be canvassed), the main use of spatial analysis is for census products and services GIS: Decision making tool Web-based applications and services United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 Conclusions Consider the Census Geography Programme as a continuous process Adapt best practices to suit specific census requirements Partner with other stakeholders (the public and private sector) in order to Build the NSDI Work jointly on coding efforts Produce value added products higher demand for census data United Nations Sub-regional Workshop on Collection and Dissemination of Socio-economic Data from Population and Housing Censuses New Delhi, India, May, 2012 THANK YOU!